[thesuperbigfrog]

>> Besides being bad behavior, is this violating the license?

Yes. Removing attribution violates the license.

https://github.com/stefansundin/2fa-qr/blob/gh-pages/LICENSE states:

"Permissions of this strong copyleft license are conditioned on making available complete source code of licensed works and modifications, which include larger works using a licensed work, under the same license. Copyright and license notices must be preserved. Contributors provide an express grant of patent rights."

By removing attribution, the "Copyright and license notices must be preserved." clause is being violated.