It's now under GNU LESSER GENERAL PUBLIC LICENSE.

There're some reasons for why I have to choose this

This is the license of the compiler itself, and I just note you can choose any license for it, even if you would link statically to LGPL (but not for GPL, that's the point of the lesser/library GPL).

For the code you emit, there's the https://en.wikipedia.org/wiki/GPL_linking_exception for linking to GPL (but not needed for LGPL).

So if you really didn't want this license (I'm not saying it's bad), then you may have limited time to go back. I only noticed two commits since from others, and one was trivial, so I think can be ignored, and the other maybe, and even if it isn't it's only for tests and they could keep LGPL (or you could ask that person).