They mentioned user-hostile in their first sentence and then went on to say the Waterfox devs were having difficulty with Quantum, so I'm really just asking about either.

I am generally just curious, as a user of Firefox. I currently trust it more than Chrome but I'm concerned if there's a trend of disimprovement.

I've commented on HN before about my concerns with some Mozilla initiatives (mainly Test Flight, but others too), but I was under the impression that Firefox core work was of a better standard.