The critics of the Boston University (B.U.) administration have long regarded B.U. as the Iran of college campuses--intolerant, tyrannical, and prone to punish dissenters.

This week the Civil Liberties Union of Massachussets (CLUM) issued a 15-page report reinforcing that view. The report--following a seven-month investigation--charged that the university had violated students's and professors' rights by censoring statements on the student radio station, by refusing to allow student fees to finance student publications, and by telling professors not to discuss in class a strike by buildings and grounds workers.

But B.U. found some solace in a dissenting statement by Alan M. Dershowitz, professor of Law and a member CLUM's advisory board.

While conceding that B.U. has probably violated the principles of academic freedom at times, Dershowitz objected to some of the methods and conclusions of the study and hinted that some members of CLUM might have been out to get the university's president, John R. Silber.

Dershowitz said the investigation should have been more rigorous and that B.U. should not have been singled out for examination. He noted yesterday that some Harvard policies are similar to those which the CLUM objected to at B.U. and added that out of fairness the CLUM should also have looked at policies at other universities.

The CLUM said in a statement it restricted its inquiry to B.U. because it "has never, in memory, received such a large and sustained volume of complaints about a single such institution."

Robert C. Bergenheim, B.U. vice president for labor and public relations, said yesterday he is preparing a detailed rebuttal of the CLUM report.