Yes it is important to apply criticism towards all sources. It is quiet clear that extremists in the political landscape are not critical at all.
They simply belief all the ideas, that verify their beliefs and disqualify all that speaks against it.
And this agenda framing is kind of what people do, when they are not critics. But rather want to lean their belief blindly towards a direction.
Yes this is the way of smallest resistance. But it rarely helps to find the truth.