I'm confident this phenomenon exists in other industries too.

Is there a term that's equivalent to "reactionary" but applies to leftist/liberal ideals or is it fine for me to start referring to this kind of writing as "reactionary" save that I apply some sort of qualifier like "leftist" or "liberal" before or afterwards?

I believe that the standard word for this is "radical", but standard use is sloppy enough that it's reasonable to seek a clearer term. I also think that "knee-jerk" may capture the quick reflexive nature you're thinking of.

It feels like the only reason to label one side of the political spectrum "reactionary" in this way is to poison the well for anyone responding to you.

Where as, pre-labeling things as being politically one-sided is very reactionary, and seems to be what you're doing here. It's also not limited to just one side of the political spectrum. I would argue that Conservatives tend to be even more reactionary than liberals. See: All the legislation to prevent children from eating from dog/cat bowls in schools when there's no evidence of this occurring.

im not sure what about this makes it left reactionary but I suppose left reactionary would be the term

The equivalent word is "radical".

Raymond Williams in Keywords: A Vocabulary of Culture and Society:

    Reactionary has become difficult because it can mean (i) opposed to reforms;
    (ii) wishing to go back to some previous condition; (iii) by application, support-
    ing a particular (right-wing) version of society. There are few difficulties when
    all impulses to change (actions) are from the Left, and all resistance (reactions)
    from the Right. But if, for example, a capitalist party is in an innovating phase, or
    if a fascist party is proposing a new social order, each side can call the other reac-
    tionary: (i) because capitalism and fascism are right-wing, reactionary, as such;
    (ii) because resistance to particular kinds of change, and especially changes and
    innovations in capitalism and capitalist society, is seen as reactionary (wishing to
    preserve or restore some other condition). Thus we can be invited to identify the
    reactionary Right (usually with a sense of the extreme Right, as distinguished
    from progressive or reforming conservatives, as well as from Liberals and the Left)
    but often, also, the reactionary Left (opposing types of change which they see as
    for the worse, or relying on particular senses of the democratic or socialist tradi-
    tion which they oppose to current changes of a different kind).

Controversially, that would be ‘woke’, but obvs the term is now somewhat tarnished.

As the right has an immovable Evangelical wing, so now does the Left. A good word for such people is currently unoccupied.

I fail to see any connections between this piece and Reaction, even tenuous ones.

Also, what would define a "leftist reactionary" anyway? An opposition to social conservatism? That's already the left's stance.

> is it fine for me to start referring to this kind of writing as "reactionary"

I really don't understand what's wrong with asking journalists to do their damn jobs and spend even a tiny amount of time checking the validity of what the people they're quoting are saying. Don't remove their statement, just point at the various potential ways they're misleading/wrong.

Journalists better start doing this basic part of their job again lest you want to be ruled by shameless incompetent buffoons that go unchallenged. Oh wait...