Freedom of speech, fine.

Incitement to (for example) racial violence - probably not fine.

Incitement to (for example) socially unacceptable other practices - where does one draw the line?

I think JM does his research in probably the only effective way, so unless we are to deny the research (which must itself be valid) we must accept the way it is done. It's not the same as actually doing harm to the non-consenting (smoking beagles in the name of tobacco research, etc)