The main motivation is to have all Weblate related repositories in one location (all others including wlc, Docker or website are already there). The move will also allow to better manage the project in future as having it in separate repositories provides less management options on GitHub than using organization.
In case you have cloned the git repository, please update
git remote set-url origin https://github.com/WeblateOrg/weblate.git
Of course all issue tracker locations have changed as well (I believe the redirect on GitHub will stay as long as I won't fork the repository, so expect it to work at least month). See GitHub documentation on repository moving.
I'm sorry for all the troubles, but I think this is really necessary move.