To be fair, I don't think the thought process usually comes from a point of planned selfishness.
Yes, the net result is that men end up with twice as many toilets (although, technically, I suppose that's not strictly true, as half of them are of restricted use by design, so men needing a poo, as well as shy men/those needing/preferring a cubicle for various privacy reasons have less provision than the women for their circumstances); but I reckon the thinking goes that there is some additional wall space where they could site a couple of urinals as well as the cubicles, do why ever wouldn't you?
It's not a conscious decision to disadvantage women, as they would doubtless happily stick a couple of extra urinals in the women's toilets too - but of course, that would be completely pointless - and wouldn't actually help women in any way; i.e. no women would actually want to try to use most of the numerically additional toilets that the men have available.
You could maybe kind of compare it to provision of sanitary bins: whereby they could equally ensure that men's cubicles are all large enough to accommodate, and dutifully supplied with, a bin - but again, it would be completely pointless and never used, except for the odd stray crisp packet that could easily go in any bin.
I think the issue is in starting off with equal spaces for both sets of toilets in the first place. As PP said, if they allocated 70% of the available toilet space to women's toilets, with considerably more cubicles, they could then put the necessary cubicles in the men's and then fill up all the remaining space with lots of urinals - so everybody is happy and fairly served.
It's a similar principle to strictly allotting equal sized bedrooms to two children for perceived fairness, even though the toddler has lots of huge bulky plastic toys and wants to run around madly all the time, whereas the teenage boy only needs/wants to sit on the bed or at his desk with his phone or laptop and rarely changes one pair of jeans and t-shirt for another identical set in any case.