Now, I can't be bothered to go back and check, but I seem to recall Bob giving Interstellar a fairly decent review. Then again, he also gave Man of Steel a fairly decent review when he first saw it, and spent pretty much every video he made since slamming the shit out of it. Now, granted, peoples opinions can change. Especially when it comes to movies. I've completely switched polarity on certain movies I've seen in my life, but this tends to happen over time, and certainly not to generate traffic on the internet (which it seems Bob tends to do a lot these days).
Having said all that, to everyone else who "cant believe" he put Interstellar in his top 20 worst (my personal opinion: much like Inception, its an interesting film, interesting premise, decent watch, disappears up its own arse in the third act, and I'll probably never watch it again), remember, this is the guy who voted Guardians of the Galaxy as the best film released this year, an (in my opinion) empty, vapid, actually quite dull action film which had huge lapses in logic and basic sense. Not really the films fault, because its like almost every other Blockbuster these days. Much like a McDonalds or Masturbation, fun while it lasts, but leaves you feeling empty and ashamed.