I don't know about those groups, but the arguments I saw so far are these:

   - Unclear maintenance - there's no clear way what to do with dysfunctional mills on land. 
     Just letting them rot seems to be a thing. Offshore maintenance is surely no fun, too. How long do they last?

   - Pollution - there's a lot of abrasion and this stuff is pretty unclear, 
     it's even going into places where clean water is collected. Does anybody care about this?

   - Ecology - there are a lot of trees that get cut down for wind. Maybe keeping those trees would be better. 
     Kills birds and bats is also part of the argument

   - Economy - a lot of energy is produced at the wrong time. So much that it's even expensive to dump.
     How much energy goes into producing the mill, and how long will it last?
     Does this break even if you subtract subsidies, maintenance and value the dumped excess-energy realistically? 
     Is there any good storage solution coming - or will this remain to be a myth?
 

In the end Economy is most likely the only thing that matters. But I guess this is not looking so good - if it would be looking good you'd see more logos of big energy companies on all these mills...