Part of someone becoming "like that" is by emulating the behavior of the leaders in their spaces. You can see this outside of any political context, even -- look at any hobby group, and you can see how newcomers determine what behavior is acceptable or desirable by looking to the most established/knowledgeable/respected members.

And if those group leaders are feds:

In 1972, a young radical Marxist named Harry “Gi” Schafer staged a demonstration at the University of New Orleans, demanding that their Students for a Democratic Society (SDS) chapter be officially chartered. Schafer climbed up on a bench, lecturing the 200 students and faculty in attendance. When the school’s dean arrived, Schafer ripped papers from the dean’s hands, called him a pig, attempted to out-shout him, and was eventually arrested alongside two others.

The next day, on a judge’s order, SDS was banned from demonstrating without permission on campus. A few months later, courts banned SDS from campus entirely. No student would join the local chapter of SDS—then the nation’s leading leftist student organization—while he was leader. SDS would never become a chartered organization at UNO, and a powerful leftist movement would not develop on campus. It was a terrible blow to organizers at the university, but it was not a miscalculation by Schafer.

Schafer was a paid FBI informant. For years he, along with his wife, Jill, spied on and undermined burgeoning leftist movements in New Orleans, well after the official termination of COINTELPRO.

How many people in leftist spaces would applaud a stunt like this if they didn't know it was a planned attempt to discredit and ostracize leftist organizations?