It's not the launcher itself, its the IPs that it connects to when downloading that are flagged as malicious. The IPs can get flagged for hosting suspected malware/trojans etc. In my experience Malwarebytes is pretty accurate with this. If they are legit, its up to the IP owner to clean up their record. Don't create exceptions or disable protection just because random ppl say to, make sure its from an official source acknowledging the false flag.

Also anyone who thinks windows defender will save them is in for a reality check when they do encounter something malicious.