Earlier quoted context omitted.
First they came for /r/ShitNiggersSay, and I did not speak out--Because I was not an asshole. [...] Then they came for me--and there was no one left to speak for me. I feel like you're skipping over a lot of slippery slope in the middle there.
If the overarching goal is to create a "safe space" and one of the tenets of that safety is "i do not have to be exposed to opinions and actions that offend me" then the slope is well greased. I'm not saying that is explicitly the case for reddit, but there are a number of internet communities who work from that definition.
The thing is, these are different goals. There's no reason to assume that a goal of "we don't want to host a forum exclusively dedicated to egregious bigotry and bullying" will necessarily morph into "we demand that all our forums be safe spaces for PTSD sufferers." You might as well say that, I dunno, installing public security cameras on a college campus will lead to the students being escorted to recess by a hall monitor, and given detention if they're not in their seats when the bell rings.