If so what makes community/universe less safe? Is there less testing or is it simply less safe because more people could put malware in them.
No, it shouldn't scare you if you're worried about safety of packages. Though I do not recommend using it since it's not officially supported. Universe is community maintained software, that is to say "not officially supported software".
I recommend you read this article so you'll understand the differences between Main, Restricted, Universe, and Multiverse repositories. Good Luck