Well, the wacky coercion rules are just one of many Javascript gotchas. I agree that most of them won't affect an experienced javascript programmer, but that doesn't mean its not a language fault. For example, in C, most programmers will know to check bounds or to use strncpy instead of strcpy, but a lot of C code that has buffer overruns still slips through.
My point is that any language fault can be memorized and worked around, but that doesn't make it go away. Also, I've noticed a lot of non-experts using javascript, so if the obvious solution isn't the correct one (using == vs using === for example), then that does cause real problems.
Note that I'm not saying Javascript is an especially bad language, just that it has, in my opinion, some severe faults.
My point is that any language fault can be memorized and worked around, but that doesn't make it go away. Also, I've noticed a lot of non-experts using javascript, so if the obvious solution isn't the correct one (using == vs using === for example), then that does cause real problems.
Note that I'm not saying Javascript is an especially bad language, just that it has, in my opinion, some severe faults.