> (3) it claims to be (memory) "safe", but requires (see 2) the use of "unsafe" features for the most basic tasks, such as implementing various collections.

I think this is an interesting one - implementing collections is (IME) the main thing one needs to use unsafe for in rust. Outside of that I barely find myself needing it at all. Unfortunately, collections are also a go-to intro project for a lot of systems programmers, so I can see how it would be easy to get a bad first impression.