However you're fighting the wrong battle here. There is some merit in your arguments and the left has often been blind to valid issues due to focusing on other concerns (spending a fair chunk of the 20th century defending Soviet oppression and mass murder springs to mind)
But that's only loosely related to the article under discussion which seems a clear, inarguable example of a portion of the right that are promoting and presumably investing in theories that are utterly bonkers.
Nobody is claiming that "believing bollocks" is the exclusive preserve of either end of the political spectrum but what's going on at the moment with QAnon, Covid denial and other extreme belief systems is surely something we should all be united in trying to fight?
I've given you an example of something that was labelled a 'conspiracy theory' by the left that turned out to be absolutely true, and in fact even worse than suspected when the truth came out. Furthermore, it was in fact the left that was engaging in conspiracy! Apart from that it's blindingly obvious that the author is using the beliefs of a minority as a vehicle to attack the (non-wingnut) majority of the right, and to delegitimise criticism of leftism.