As for Gitlab and Github, I left ridiculous Jabbascript abominations behind and never looked back; Github now overriding usual keys like PageUp/Down and Home/End SPA style and not being able to display most stuff without JS is the straw that broke the camel's back for me.
It's not a very useful metric. A user having a flaky internet connection with high latency and low bandwidth and intermittent disconnections would complain that the platforms he uses are "slow".
Or a service is just bogged down by too many users but would be quite responsive if not overloaded.
EDIT: I was not writing about JIRA specifically. I agree that JIRA is ALWAYS slow. Ten years ago I had to wait five seconds after a button click. However I also had to handle a complain that something was slow just because that customer's internet was shit.
EDIT 2: I remember ten years ago an especially perverse variation. A friend of mine was complaining about the bad quality of video even after having upgraded his internet connection. The problem was asymmetric bandwidth. His friend had bad upstream and my friend just saw jerky movements and ugly artifacts and it was unusable for communication in a Signed Language.
I learnt that day: if something is slow, then it is not always easy to understand why. My friend was very disappointed in me.
On the contrary, a bad internet connection makes it much easier to distinguish slow and fast platforms.
Video tends to be bad for the receiver if the sender has bad upstream.
That being said, I haven't seen anything egregious for a couple of years, so maybe he's taken some of the honest feedback to heart.
The problem is that SourceHut is not becoming any better over time. With all my respect to Drew, his attention is spread too thin over many projects.