Is this really a unique to R or do all programming languages have some foibles? For example I spent an hour recently debugging C++ because I forgot that it loves to do integer division despite the fact it's going into an explicitly typed double. No error, no warning. You just have to know and I highly doubt it's desired behavior for most cases.

Most researchers are not programmers and don't care about programming. It's a tool to get the job done and I think you'd run into similar problems with other languages.