I can only think you must have been watching a different interview trisher!
I saw Marr make a fool of himself quoting soundbites from years ago, instead of the real news, which is what the Brexit party has achieved in just four weeks.
What I watched was Marr rattled by Farage. His questions, merely a list of you said this, then you said that from years ago, without discussing why the Brexit Party might be in such a significant lead in the polls, what strategy the party might use if it has to take up its seats in the EU. Marr obsessed about a Free Trade Deal, which was answered 4 times, perfectly clearly, yet Marr kept on like a dog with a bone.
Then domestic questions about NHS, irrelevant in the EU elections. There's nothing wrong with being asked difficult or challenging questions but they should be relevant and topical. If you watch the programme beyond the Farage interview to the next interview with the Labour chap (Jon Ashworth), it was a different tone altogether, perhaps reinforcing, that those who will vote Farage, see Marr and the BBC as the same old, same old, part of the establishment trying anything and everything to overturn the referendum result.