I think feelings and personal beliefs should stay as far as possible from philosophy. Philosophy should never evolve around subjectivity such as feelings; philosophy is an attempt to be as rational and logical as possible in albeit a very subjective world. Much of philosophical arguments are made in same manner as discrete mathematics because of this but with words rather than formulas and rules. Even religious medieval philosophers attempted to be as logical as possible in their approach to explaining religion rather than relying on belief (though often fail despite their best attempts). So the "feeling of unsafe environment" isn't something I see as compatible with any philosophical discussion as a basis of reason. There needs to be an objective as possible pivot.

We see plenty of vastly different feeling of unsafe in social media. Some of which even do so with the intent of not actually feeling unsafe but to garner views and likes. If someone is scared by everything, can we start intolerating everyone else? We don't know where the line can be drawn between being a just society that tolerates freedoms and the one where tolerable can no longer exist.

This is why Popper proposed the entire dilemma. The violence being the pivot of intolerable intolerance isn't his opinion. It is that with violence, tolerable objectively (as much as we can be objective) cannot exist.

Even in your example, you attempt to separate objectivity vs subjectivity in are/is versus believe respectively for the sole correctness of the former. (Even though in my view, proof of what is is going to end up as sum of your beliefs or a cyclic viewpoint.) And then the argument goes back to pivoting in the subjectivity of feelings.

If you rely on subjectivity to draw the line of what's intolerable intolerance, then you will be intolerant of people who you subjectively view as intolerable.

You cannot reason someone out of a position they did not reason themselves into.

That's merely an assumption based on a stereotype you have about people like this. Just because reason may have failed with other people like that in the past doesn't mean it's not going to work with this one, especially if you haven't even tried to reason with them and immediately go for the bigger gun of ostracism (i.e. firing).

It is not reasonable to deprive someone of their source of income for having an opinion you don't like. It IS reasonable to tell them that their opinion doesn't belong in the company chat, and give them a warning that disciplinary action may result if they do it again.

Nobody else should have to put up with an uncomfortable work environment, social club, or anything else, because we have to make accommodations to be tolerant of bigots.

You're excusing hatred with bigotry. The same argument could be used to exclude transgender people.