They used the account only to announce disruptions - and didn't lock comments/replies.

So obviously on some of those posts you would see replies from people annoyed by specific disruptions.

The weird thing is that you actually need to spend time to find any replies - as most announcements didn't have replies.

And those I found only reached the "sarcastically formed hypothetical question". And still often being on point - e.g. why are there no fallback buses to cover tram/metro disruptions.

Considering all that - it seems "constant hateful messages" is at least a bit exaggerated.