The way to ram a broken bot is indeed to force ram them, only possible with the keyboard as a rare exception. If your input didn't even register then you must've entered it incorrectly somehow, or made some other mistake. (Note that you cannot use vi keys to force ram, because that overlaps with part interaction commands. That will indeed simply not register if you don't yet have parts matching those letters. You have to use another movement key in that scenario.) When you attempt to force ram, it'll give you the normal ram warning, and a second one will ram the broken bot.
Ramming broken bots was indeed originally not possible, but this feature was added several versions back.