I totally agree that they should have left a note on the issue tracker - even if they thought it would go unread. However I think you're being a little unfair on this one point.

>there was no interest in helping out the project.

They saw that people were filing issues and making pull requests and that those people were getting total radio silence. I can understand how someone might think "well, people are already trying to 'help the project' and the maintainer isn't even acknowledging it, so it's a waste of time".

And while again I totally understand and agree that they should have tried to contact you, you've known about the removal for like 9 months and you apparently never reached out to them either? Like, a couple words in reply to a bugzilla or an IRC message does not amount to picking a fight with a company.