Part of the problem arises from an unhealthy attitude that bug reporting is a service that benefits the tester.
Could you please cite your source? Is there a document or mailing list thread that states that this is the reason that those services do not have onion endpoints?
The Debian project is unapologetically telling testers to switch to clearnet and mainstream browsers when the bug services discriminate against users based on the network or browser version they use.
Where are they saying this? Are they actually treating connections from Tor exit nodes or Torbrowser differently?