If the appointment process is governed by statutory recruitment rules under the WBCSC framework, the college’s discretion after recommendation may be very limited.
If the candidate was validly empanelled and allotted through centralized counselling, the institution may need to show the statutory authority to reject,
pre-existing service rules, or disqualification criteria already disclosed.
If no such rule existed, a later justification can be attacked as arbitrary, mala fide,afterthought reasoning, or violation of Article 14 principles.
If the candidate was never given a show-cause notice,
informed of objectionable posts, or allowed to explain/contextualize them, then denial of joining may be challenged as violating principles of natural justice.
You can file writ petition seeking mandamus directing joining/appointment, quashing of refusal decision,
continuity benefits/seniority, notional salary, or fresh consideration through a reasoned order.

The Calcutta High Court has ruled that a government-aided college cannot deny employment to a recommended candidate merely based on personal social media posts or ideological differences. In the landmark case of Tamal Dasgupta v. The State of West Bengal & Ors., Justice Partha Sarathi Chatterjee directed Rama Krishna Mission Residential College (Autonomous), Narendrapur to issue the appointment letter within four weeks, affirming that freedom of thought cannot be sacrificed for ideological conformity

I have considered the facts stated by you regarding the recommendation issued by the West Bengal College Service Commission in favour of the empanelled candidate, the subsequent refusal by Ramakrishna Mission Residential College (Autonomous), Narendrapur to permit joining despite counselling and recommendation, and the later justification sought to be introduced by the college based on alleged objectionable social media posts.

On the facts disclosed, the candidate appears to have a substantial and arguable case in writ jurisdiction before the Hon’ble Calcutta High Court.

Once a candidate is duly selected through a statutory recruitment process, participates in counselling based on merit, and receives a formal recommendation from the Commission directing appointment/joining, the concerned institution ordinarily cannot arbitrarily refuse appointment unless there exists:

• a statutory disqualification;
• suppression of material facts;
• proven misconduct;
• failure to satisfy prescribed eligibility conditions;
• or other legally sustainable grounds.

A very important factor in your case is the apparent delay and shifting stand of the college. As per your narration, initially the college allegedly did not communicate any valid ground for refusal, and only after the writ petition remained pending for more than a year did the issue of social media posts emerge as justification. Courts generally view post facto reasons with caution, especially where:

• no contemporaneous order/reasoned communication existed;
• no show-cause notice was issued;
• no opportunity of hearing was granted;
• and the objection was not part of the original recruitment criteria.

If the alleged social media posts were neither:

• prohibited under recruitment rules,
• nor disclosed as disqualifying conduct in the advertisement/service rules,
  then denial of appointment solely on subjective institutional displeasure may be vulnerable to challenge as arbitrary and violative of Articles 14 and 16 of the Constitution of India.

At the same time, one important nuance must be appreciated. Educational and minority/autonomous institutions, particularly value-based institutions such as those run by religious or charitable organizations, may argue that they possess limited autonomy to preserve institutional ethos and discipline standards. The college may therefore attempt to contend that the candidate’s public conduct is incompatible with the values of the institution.

However, even such institutional autonomy is not absolute where the appointment process itself is governed substantially through statutory selection by a public recruitment body like the WBCSC. Once the Commission has recommended appointment, the institution cannot ordinarily introduce vague or undisclosed moral standards retrospectively unless supported by service rules, governing statutes, or clearly established institutional regulations.

Another important aspect is whether:

• the social media posts are genuinely unlawful/hateful/abusive; or
• merely ideological, political, personal, or critical expressions.

Courts are generally reluctant to sustain denial of public employment solely on the basis of lawful personal expression unless it directly impacts service eligibility, institutional functioning, or statutory norms.

The candidate’s strongest legal points appear to be:

• merit-based selection through statutory process;
• issuance of recommendation letter;
• absence of timely reasoned rejection;
• delayed introduction of new grounds;
• absence of due process;
• and legitimate expectation of appointment.

The reliefs ordinarily sought in such matters may include:

• quashing of the refusal action;
• direction to permit joining/issue appointment;
• consequential service benefits;
• and in some cases notional seniority.

However, practical outcomes in service writs can vary depending upon:

• the exact nature/content of the social media posts;
• whether the college is aided/autonomous/minority-administered;
• the wording of applicable service regulations;
• and judicial balancing between institutional autonomy and equality in public employment.

You should ensure that the following documents are properly placed before the Court:

• advertisement and recruitment rules;
• counselling records;
• recommendation letter issued by WBCSC;
• correspondence with the college;
• any refusal communication;
• affidavit/opposition filed by the college;
• and exact copies of the allegedly objectionable posts.

If the posts are being selectively quoted or taken out of context, contextual explanation becomes important.

Overall, based on the facts presently stated, the delayed reliance on social media posts after institution of writ proceedings appears legally vulnerable and may be challenged as an afterthought and arbitrary exercise of power.