ORM are bad if you look at things from a DB perspective.
If you're an application developer you've seen what happens what the code dissolves to if developers are rolling their own queries all over the place and doing manual model to object mapping. ORMs have appeal in environments they provide tooling on top and where developers are expected to know how to use them (Entity Framework, Django admin). In other situations like Clojure I would just use something like yesql.
One trap I've seen with big ORMs is some coders stop "thinking database", which can lead to performance problems.
The "N+1 selects" problem ( http://use-the-index-luke.com/sql/join/nested-loops-join-n1-... -- running for loops against nested selects) is probably the most notorious case of this. When you learn SQL, you pretty much learn from the get go that loops are bad (eg, you avoid cursors, and process things in batch, as much as possible). I think it's a lot less obvious that this also is the case in ORM land, that for loop doesn't instinctively look too dangerous when you first start programming using an ORM. (Because in your regular code, it really wouldn't be.)
Personally, I do quite like micro-ORMs like Dapper. Dapper's great at mapping query results to objects, but still allow you to take advantage of SQL performance.
The thing with ORMs is that they buy you a lot of fancy stuff as well - scaffolding/crud templates, they integrate in to your development workflow (under source control, in the same language as the rest of your code base).
I'm not really a fan of ORMs - I think it's fundamentally an inferior approach and I think clojure/yesql or (presumably) Dapper like micro ORMs are much better where you treat query results like values instead of objects - but at the same time an enormous ammount of work went in to ORMs and a lot of developers are familiar with them to the point where they can do their job in 90% of the cases - and for that 10% case you have the senior dev or a DBA can step in - this IMO is a big value proposition that shouldn't be ignored.
If you're an application developer you've seen what happens what the code dissolves to if developers are rolling their own queries all over the place and doing manual model to object mapping. ORMs have appeal in environments they provide tooling on top and where developers are expected to know how to use them (Entity Framework, Django admin). In other situations like Clojure I would just use something like yesql.