No. I said it "may well be", because a naive implementation using a native language may block while doing IO and be less responsive, unable to do other things while waiting for external stuff to happen.
Perhaps I should have said "may well be more responsive than".
So, you don't actually know anything about whether native apps block on IO? (I doubt they do on any modern version of Windows, OS X, Linux, Android, iOS or Windows Phone.)
Perhaps I should have said "may well be more responsive than".