I suppose you know how timing side channel attacks are done? All those layers of abstraction make it possible to accurately predict and alter code path length? Oh, and they do automatically handle things like proper memory scrubbing of keys when no-longer valid? Right?
These things need low level hardware access to manage, and are hard even then where there is less in the way screwing with it. It is nearly impossible to handle properly on highly abstracted languages running in managed virtual environments like Java and C#.
Yes those abstractions help avoid specific classes of vulnerabilities, but can open a whole host of just as bad context specific ones when talking about security stuff like encryption. This is why we should only let specialists in that specific field do such implementations and have them vet each others code.