Critical thinking is not necessarily opposed to the status quo. To criticize is not to oppose, but to sift, to assess, to assay, to evaluate. The etymology of krinein suggests as much. A critical thinker may well end up supporting the existing state of things in this or that respect. It is a fallacy of the Left to think that any supporter of any aspect of the status quo is an 'apologist' for it in some pejorative sense of this term. After all, some aspects of the status quo may be very good indeed, and others may be unimprovable without making things worse in other respects.
The notion that critical thinking entails opposition to the status quo presumably has its roots in the nihilism of the Left. Leftists are often incapable of appreciating what actually exists because they measure it against a standard that does not exist, and that in many cases cannot exist. It is the leftist Nowhere Man who judges the topos quo from the vantage point of utopia. There is no place like utopia, of course, but only because utopia is no place at all.
Just as leftists do not own dissent, they are not the sole proprietors of a critical attitude. Kritische Theorie as used by members of the Frankfurt School is a tendentious and self-serving expression.