To put it another way...

If you try to use an object-oriented approach in Haskell, you're going to find the experience a little frustrating, and you'll feel the language is rigid.
If you try to use a functional approach in Java, C++, etc., you're going to find the experience a little frustrating, and you'll feel the language is rigid.

A few weeks ago I did a bit of PHP programming for a client, and discovered that PHP won't warn you if you use a variable without declaring it. Now that's what I call flexible! But instead of rejoicing in that flexibility, I was annoyed.