> Apple-maintained antivirus system called XProtect which works great
Earlier this year it began detecting Apple-distributed iOS simulator bundles as malware and deleted those [0]. This was a major headache for several days as different headless CI systems developed the problem; we could not figure out how to get a 'good' version of XProtect installed in-place and ended up removing and rebuilding machines.
Bad antivirus software is indeed terrible, but the good stuff is performant and invisible.