No one wanted Musk to put in an offer on Twitter, except Musk. Musk needed to put together such a good offer, that Twitter's management could not block it. Part of that offer was to pass on due diligence. That was done without request, or negotiation. Musk literally signed a contract, without any pushing, that the facts of Twitter do not matter.
There is no standard way to measure bots, or even what is a bot compared to what is not a bot. Best guess is it is between 9% and 15%, which is why Iger decided to back out of the deal. Musk knew Iger had backed out of the deal, and why.
Put another way, even if every user of Twitter is a bot, Musk already stated it does not matter, and Twitter depended on Musk's representation, and so Musk would lose the case. That is why Musk is going through with the deal now.