First off, proximity to the Kotel is not in any way a reliable indicator of prestige or influence, and the statement of one Rabbi (even a highly influential one in a high position at a prestigious institution) does not necessarily indicate a universal doctrine.
But regardless, now I'm a bit unclear of what you're saying.
Was the question (1) Why is this Yeshiva not co-ed?, (2) Am I allowed to learn with a woman?, (3) Am I allowed to learn with a woman in the Beis Medrash?, (4) Why don't women learn Torah/in Yeshiva?, or (5) something else?
More importantly, was the answer (1) Because co-education is not conducive to the kind of focus and immersion that Yeshivot strive to engender, (2) Because boys in the age group of Yeshiva students will tend to be distracted vein their learning if there are women around, (3) Because women are inherently distracting to men, regardless of what positive qualities they might bring to the table, (4) Because women are nothing more than distracting sexual objects without intelligence or insight of their own, or (5) other?
The way you presented it, it sounded like the question was (1) and the answer was (4). It's not impossible that this is what happened, as it is possible to hold a high position at a Yeshiva and still be unwise or ignorant. But it's highly unlikely. I don't think I've ever heard that opinion publicly expressed in Orthodox circles, and I don't think there are many people who think that privately, either.
Answer (3) is a more commonly held view, even though I think it's extremely problematic. And it's definitely not a core belief of Orthodoxy.
I won't go into every combination, but the idea that co-education or having women around can result in more challenges than its benefits would be worth is hardly outrageous, certainly isn't misogynistic or archaic, and isn't limited to religiously conservative communities. So if that's what you're responding to, I think you're being quite silly.
I'm not trying to "convert" you; I'm sure you have other reasons for not being Orthodox, and even if you don't, your mind is clearly made up, I just want to clear this up to avoid anyone reading this thread to be tragically misinformed.
I will say that if this is your main claim against Orthodoxy (which I'm sure is unlikely), I think it's extremely ill considered. The offending view (even in the non-crazy versions) is not universal by any means, and even if it were, it isn't that much of a big deal, especially outside of Yeshiva.