I agree with your evaluation that parts of the FP community are extremely vocal and extremely smug, and this can and does have a bad effect on a community. This is a problem. Dealing with this problem requires leadership. In particular a project leader typically has to decide (in a Scala context) whether to go FP or imperative, because mixing both is often a problem. Similar to e.g. using message passing or shared memory for communication between threads.

    throw exception 

This is a good example. It is really important to be very clear from Day 1 how to handle errors in a project. One hybrid choice that is popular is: use exceptions for errors that you cannot recover from, use Options for local error handling.