I think Phil is largely the one people consider to be responsible because he was the only big channel - at the time - to immediately call them out on what they were doing. Keemstar, while I have no respect for the man, played called on Devil's Advocate because that's just how he gets his views: he stirs up a bunch of drama or uses bullshit like "I grew up in a family like that and turned out fine" excuses to take the obvious unsavoury side of a story.
Which, honestly, is probably why it came to be such a shock to everybody when Keemstar then turned around later, after an interview with them and after more videos surfaced due to the digging everybody else had been doing into the channel, and said that the family were deplorable and he no longer had any wish to even try and defend them. So... yeah. In that one regard alone, Phil was definitely the first big channel to scoop the story and make it viral fast - and was the only one the family hit out against on their own channel - but he certainly wasn't the only big channel that got the story spread or did the digging.
I think my biggest issue with Phillip is that he can get very preachy in a lot of his stories. He'll offer unbiased reporting
on the story itself, and then offer his opinion and that by itself is fine. The problem I tend to find is that he very rarely seems to actually open up the "discussions" he claims to want to have with his viewers by finding good counter-points to his arguments and actually considering them in follow up episodes. A good example of this is when he was dealing with the Nazi that got punched in the face: his stance was that we needed to "talk to them" and not "fall to their level".
Plenty of people, myself included, left comments explaining why that moderate-pacifist bullshit just
doesn't work and is the very reason that fascism continues to breed in modern society - because moderate-pacifist people like himself preach about how important "free speech" is without ever condoning the fact that free speech doesn't free you from consequence and also
maybe people who believe that minorities need to die don't deserve to spread violent hate rhetoric. Never - never once
ever since that episode - did I see Phillip pick up any of these comments and discuss them. He/his team picked comments that were easy to either shoot down for obvious stupidity or ones that agreed with him.
So in that regard, I find his content is a little bias. He's good to watch for seeing news stories with few bias, but when it comes to his actual opinions on things he can not only be preachy, but he never defends them from legitimate counterpoints and he's almost an extreme apologist. Like his content or not, I can't pretend that I have respect for somebody who thinks Nazis deserve to have a platform to talk from just because "free speech" is a thing, nor do I really have respect for somebody who will go out of his way to be an apologist for shitty behaviour. (The recent PewDiePie bullshit is a good example of this: even when he admits Felix probably uses the N-slur in real life if it came out of his mouth so easily, Phil finds excuses to tell us how much of a good guy Felix is and how his apology was "so right" even though the apology was the biggest crock of shit seven ways to Sunday.)