Object-oriented Design in Ruby/Rails

In a discussion about design and ruby/rails apps, a statement has been brought up as a counter argument against the use of trailblazer, DDD techniques and Rails (best/standard) practices to tame complexity. And that is that "[...] there are cases where 300+ lines of a Ruby class are the right thing". Just to be clear, these 300 lines are pure LoC, no comments or line breaks (I already subtracted those away).

I cannot believe that's even close to true, but nevertheless I would like to know the opinion of the Ruby/Rails community. Can you really think of such (valid) use cases and or did you even come across those (apart from anti-pattern use cases)?