Because everyone in the community for the most part have become close friends over time. Valle can even get along with and have fun with marn at times. Just in different ways. That video is a short clip of a night long event. It's like how the worst parts are always the parts that get shown over the funny or good memories.
I realize they're friends. But this I think is a bigger deal than the jokes themselves. It doesn't seem like the FGC is taking this as a serious issue at all. It's just a joking matter, something that'll blow over in a couple of days. inkblot's statement notwithstanding.
If you're actually trying to let the outside media know that 'hey, we're not really like that', then you keep someone who'll make exactly that sort of joke off mic.
Edit: And for people claiming that this is sensationalistic, you should be aware that if they wanted to dig they could find a lot more dirt. It'd take more work, naturally, but there's all sorts of streams out there from after the Miranda thing. Hell, marn was on stream with mike ross, and I couldn't watch the whole thing in archive. So if they wanted to cherrypick the very worst, they could probably do much worse.