I can totally understand that protesters get kicked out of a conference. Although there are ways to handle it professionally and non violently ofcourse
Find a public square, get a permit and you can rant all day about Jesus, Palestine or space lizards.
The editor-in-chief of a journal handing out a paper that was published in that journal at a conference for that journal... is quite different from ranting about space lizards in a public square.
Your argument is a strawman: you are refuting an argument different from the one actually under discussion. The argument isn't "is protesting at a conference acceptable?" The argument is "does this behavior constitute an unacceptable protest?"