Sorry bro but they're right, your rant was weird, unhinged and sexist
Not being able to form friendships of the opposite sex just means you're too low intelligence to be able to relate with someone different from yourself and/or such a shitty person you can't form a 'friendship' with someone if you don't see there being a benefit to yourself in it
Then let me clarify, i do not speak in absolutes i.e. it isn't impossible nor is it very rare. The fact is that a lot of those relationships are usually formed DUE to someone having a clear interest in intimate relationships (DOESN'T MEAN SEX). (speaking about girl x boy)
Next point, can you make friendships with women? Sure you can, like i told I had friendships DURING MY SCHOOL YEARS AND YOUNG ADULT PHASE. But let's be intellectually honest, if you are a "normal" guy your usual interests and do not intervene with usual "normal" girl interests.
A) Let's say for example martial arts, table top games, gaming, poker and etc. <-- These are majority of men hobbies, there aren't a lot of women interested in these, there are some women that are but let's say out of 5 people at best you get 1 woman.
B) Next camping, cycling, dancing(with pairs), traveling and etc. these hobbies are more or less 50/50
C) Cooking, book reading clubs, tailoring, shopping, beautifying(saloons and etc.) and etc. T <--- These are majority women hobbies
Next we add to that mix gender experience, men and women have different experiences and thought patterns which makes it a bit harder to form a smooth connection which results in harder connection i.e. Harder to have a smooth friendly relationship due to differences in views.
We also add social norms to the mix if stars aligned, she has a boyfriend(or a husband and children). It is viewed weird and "risky" when you meet with a married or taken women alone. Many women and men have problems with that when their loved ones meet someone of the opposite gender in 1 on 1 setting. We can also add a group of old friends but with age it's quite hard to have those meets due to family life.
My case specifically we had mixed friend groups but with time and age we dispersed, now many of my past female friends have children and husbands, some can allow to meet (i.e. husbands are okay with them going out with male friends) but they also have a strong detergent called children. Next point about those women with children, they aren't as interested in things we had common interest with, they have completely new set of problems and interests due to forming family.
Let's return to NORMS, normal means a vast majority, norms can shift one day it was normal to see emo's and goths now it is rare to see those subcultures.
Friendships are usually made if you have common interests (at least initial stages), later on you form connections and common experiences (you make deeper connections) the problem is that in majority of cases when you lose common interests you meet those friends less and less and even those deeper connections eventually get lost. I had male friends with whom i had deep connections during my younger years, with time we lost common interests but our relationships persevered but due to various circumstances started to decline. With time we started to call and meet each other less and less due distance, lack of common interests and etc. We couldn't not maintain interest in those relationship just due to shared past experiences.
Lastly the low intelligence thing, hey you might be right about low intelligence (my intelligence personally not the correlation with understanding others i can relate to many people but that is personality trait. I can relate to people who do drugs or sell them (literally had people in my circle) but if i can relate to them doesn't mean i want to associate with them).
BUT low intelligence doesn't relate to having a lot of friends i would even say the opposite is true medium and low intelligence people have a lot more friends . We tend to form friendships with people with whom we share intelligence level. Just think that people with IQ 130-160 would not be interested in a person with 80-100 and/or vice versa. BTW ONCE AGAIN I DO NOT SPEAK IN ABSOLUTES there are always outliers. Also let's not forget extraversion and introversion.
Sorry for the long post, i just needed to clarify a few things some people lack reading comprehension and/or always think that some people talk in absolutes which is mildly irritating.