Maybe so but it wouldn't be the case if the other parties did their job and denounced the abuses from the EU when those happen.
Instead, it leaves the parties on the fringe as the only ones doing the criticizing.
Why should it be controversial to say that the EU is not perfect and that leaving it could work out better for certain countries?
Instead it's like no one can imagine a time where the EU did not exist and it's almost like we have forgotten that the EU is not the end all be all of everything.
But yes for sure there should be other parties, or/and the tiny ones that do a great job on internet matters such as the pirate party should get a lot more votes.