The name ShinyHunters is currently quite well-known due to a number of high-profile hacks (Odido in the Netherlands this year was huge). Their brand has a significant value right now.
Because ShinyHunters published they hacked Canvas on their own website.
They also redirected the canvas login pages to a ShinyHunters message, whilst this could be done by another group/person, its unlikely.
You can also validate PGP keys and TOX accounts, etc via their website.