I don't believe that most of the people who have voiced their concerns are calling for "100% pure free speech", and I would appreciate dropping this strawman. Death threats and personal attacks against users shouldn't be okay. But if you want to start coming after content that makes edgy jokes or whatever, you need to have a damn good reason, and Derpibooru did not have a damn good reason. The reason you don't see people here saying "nigger jew" left and right is because being able to say these things isn't why most people here are leaving Derpi, we are simply concerned about the precedent that it sets to start retroactively deleting art because it made some people uncomfortable.
Inb4 Slippery Slope. It's not a fallacy if the slope can be observed. And even if we couldn't show it, how is it any more of a slippery slope to say "censorship doesn't stop at one" than it is to say "if you let people speak their mind minorities might be sad :("? Obviously we don't want people running around random comment sections calling each other slurs (and admittedly, a more developed rule0 policy than "Don't be a dick" may be useful), but I cannot support banning content that might hurt a feeling. There's tons of crap out there that I don't like, and I don't complain about it ruining Derpi/Pony/Whateverbooru because I know how to use filters. This was always the solution on Derpibooru to avoid having to deal with stuff you don't like, and I fail to understand what exactly the problem was with that.
If, or when, Ponybooru staff decide to place limiters of what can be said, they need to be careful that they do so _*fairly_*. Make this shit apply to both sides - if you want to see an example of what I'm saying not to do, simply go to Derpi forums and see how desperately the staff is trying to defend "promoting violence" against certain groups of people while banning content that's "promoting violence" against others. I don't agree with banning any of it, so long as it's not targeted at specific people, but there needs to be no bias here.
Either way, for what it's worth, I do appreciate you taking your time to voice concerns. It can't do anything but help the site if you convince staff to think about these things, which puts you leagues above those who would rather see any of these altboorus fail simply because they aren't DERPIbooru.