“It’s okay to ban speech I find offensive” becomes “ it’s OK to ban speech deemed offensive by this committee” when it becomes policy. Then the committee becomes a target for influence or corruption, because if you control the committee then you control speech. This is bad whether we are talking about governments or corporations, if those corporations have monopoly or oligarchy control over platforms of discourse.

That’s why it’s generally a good idea to only ban speech which is threatening direct violence, or inciting violence, or other very specific things. “Ban fascists” is too broad.