For me, it's actually easier to trust sources like unionriot.ninja — though by "trust", I don't mean "take them at their word". It's more like a "I understand how to situate this journalism within its wider context". Which is to say that I find them easier to vibe check.

I find smaller outlets like this are often pretty good with their sourcing. For the example, from these guys, I think I read some really good coverage of some specific issues in the prison system. The article was clearly written to persuade (and as you say, clearly left wing), but the way it was doing that felt transparent. In particular, I think there was a quote they used from a legal expert, but they also included links to that person's work/full quote, which makes it easier for a keen reader to vibe check the person. I like their transparency.

I agree that it's hard to place them on a "reliable" spectrum. My instinct would be to place them quite high, because the fact they're open about their biases (i.e. left wing perspective) and they are good at citing sources makes it easier for me to evaluate their work. However, that doesn't feel right when we consider what kind of news outlets would typically sit there — many of our heuristics for parsing media are still anchored in a more traditional model of news coverage, which these guys clearly aren't.