I wouldn't call Maher a liberal? I'd probably call him a left-leaning moderate.
Okay, feel free to go around saying you're going to kill Trump and see what happens
There's not much that's "moderate" about Maher.
I always find it weird coming back to Neogaf and remembering everyone just uses American terminology wholesale. I think Europe has a much more exact way of talking about it.
Basically, "liberal" is the political tradition that probably starts at the Magna Carta, winds through Hamilton and Smith, then Mill, and is based on the idea of individualism, enumerated rights, limits on the power of government, etc. They're orthogonal to the standard left-right axis, for the most part. Libertarians occasionally call themselves "classical liberals" for this reason, attempting to claim the entire tradition for themselves, but most agree that the movement diverged into its right and left form sometime after Mill in the mid 1800s.
Left-liberals are Maher, the ACLU, and anyone that shares broadly leftist goals and prefer to promote them within a liberal framework of individual rights, constitutional protections, etc. They most often argue from a sort of third-person neutral arbiter position, where it is assumed that holding fast to stated principles and ideas will make it possible to hold the other side to those neutral principles.
The illiberal left are the no-platformers, the more strident elements of the social justice movement, and more or less anyone who thinks holding both sides to neutral principles are impossible. They will generally take your view that applying facially neutral principles to the other side is impossible and that victory is important enough to make promoting those principles a secondary concern. Or, as you put it, that the fact that we are in a culture war makes no-platforming a necessity.
So the ACLU can yell illiberal leftists for abandoning all principle, and the illiberal leftists can yell at the ACLU for having secret right sympathies or of not takign the threat seriously enough.
(right-liberals are generally libertarians and right-illiberals are, well, most conservatives in the US)
I haven't done a good enough job making those descriptions neutral, and perhaps the terminology itself is prejudicial, but I think you've got the idea. There's a pretty big schism in the American left along these lines now, and I think making such distinctions is important in determining where it's headed. It's pretty clear that the left liberals are losing ground, to the point of someone in this thread describing the ACLU as a mixed bag. Which side ultimately lays claim to represent the American left is one of the most important stories of this decade, in my opinion.