This seems like an excellent reason for men to object to PUA: it focuses mainly on one night stands and short term relationships,

I've posted some thoughts on the orientation of PUAs to relationships. Although many PUAs do focus on short term relationships, most of what they are doing would be the same even for long-term relationships.

As far as I can tell, limiting factor of most PUAs in attracting women for either short-term or long-term relationships is that they are insufficiently masculine, high-status, and exciting. At least, with young women, who may well be skewed towards short-term mating (contra the stereotypical assumption that women always want relationships).

Young men are often accused of being "led by their dicks" when choosing mates. I think there is something analogous going on with young women. Even though in the abstract they may want relationships, they also want highly sexually attractive guys. And the most sexually attractive guy out there for many women isn't necessarily the guy who would make a good long-term relationship partner.

So if you are a young guy and you want a relationship with a young woman, you have to deal with competition from guys running a flashy short-term mating strategy. For a woman to notice you and be interested in getting to know you well enough to even think of you as a long-term mate, you have to outshine the local badboys. If you try to present yourself as stable, romantic, long-term mate from the start, you will be consistently overlooked.

Of course, not all women are following this type of mating strategy where most of their attention goes to the flashiest males, who they then try to "convert" into long-term mates. In fact, I'm willing to bet that there is at least a reasonable minority of women who only go for long-term mates. But it's common enough that men need to be aware of it. It pays for young men to have the kind of flashy presentation that PUAs teach, regardless of whether they are looking for short-term or long-term relationships.

which may reduce the ease and likelihood of pair bonding for the woman, later in life

I've seen this idea before, but I wonder if we actually have any empirical evidence that it is true that short-term mating reduces the likelihood of pair bonding for women later in life. My gut reaction is that this may be true for some female phenotypes, but not for others.