There is a whole chapter about it, and it's not mysogonic. He addressed the problem of females who simply eat and drink for free EXPLOITING stupid dudes as the default mode of partying. That's why he is hostile to them with

I highly recommend reading it. It's not worse than calling someone who exploits drunk women as 'dickhead'.

Lastly the word 'bitch' used here is an important part of the particular story where he used it against particular women who scammed him during the confrontation later.

Read it as whole

I have read the whole chapter, and my criticism is not based on taking a single quote out of context. Your framing reduces women in that environment to a single stereotype ("girls exploiting men for drinks"), and the suggested response is to adopt deliberate hostility and disrespect as a strategy; it is generalizing an entire group and justifying contempt toward them. The "lesson" explicitly encourages treating interactions as transactional and frames social interaction primarily as a negotiation for sex. Whether or not some individuals behave opportunistically, promoting that mindset as a general rule is ethically questionable.

Most importantly, the outcome does not validate the approach as healthy behaviour and even Feynman himself makes it clear at the end that the method was effective in a narrow sense but not enjoyable or aligned with how he ultimately wanted to interact with people. That distancing is important context: it suggests the episode was more an observation about social dynamics than a recommendation for how people should behave.

Not buying drinks for strangers is NOT bad advice. Best of all: he is right. Just ask women or people who party a lot :) .