Yes, sexism is likely to blame for quite a bit of that. There are gender roles that people are steered towards in society regardless of their actual aptitude and this is WELL established by the empirical research. I mean do you really think women are massively overrepresented as secretaries because they like taking notes and typing?
I really don't understand this. That people don't work according to their aptitude is proof of absolutely nothing. I've a strong aptitude to music, as attested by my two older siblings, both professional musicians, yet I didn't pursue a career in it because it didn't interest me despite my talent. The same goes for my wife who, despite copious praise from her superiors, peers, and patients, has a real aptitude for nursing yet is leaving the field in general because she detests it.
Societal pressure may play a part in how people choose their jobs, but so certainly, and certainly more so, do people's own interests.
To answer your question, I think women are overrepresented as secretaries because they prefer it much more than men do.
Do you think men are overrepresented as those who shovel the snow from the walk because they like shoveling snow? Or getting nasty and dirty on oil rigs because they like getting nasty and dirty?
It's baffling that you would be so blind. I mean you are honestly trying to argue that there were almost no black quarterbacks at all in the NFL until recently because black people just didn't like playing the most prestigious and highest paid position. That's /facepalm worthy. You can't actually believe that sort of ridiculous nonsense. As for why black people significantly outnumber whites in football, they do so in most sports. This is likely primarily due to the incentives offered to them throughout life and yes, racism is a likely component.
I'm sorry but I am blind to what I can't possibly see. For you, there doesn't seem to be any racial disparity for which racism isn't the very first and primary explanation. If your theory about quarterbacks is true, it would follow that whites would be discouraged from punters and field-goal kicker positions since they're at the very bottom of the prestige-and-pay totem pole. Yet whites dominate the kicking position by even greater margins than they do quarterbacks. How do you reconcile that?
This is an obvious straw man. No one has ever argued they should be exactly the same.
Then what would the racial makeup of the NFL have to be, or the sexual makeup of those in secretarial positions, before you thought the accusation of racism or sexism was unjustified?
Well then I guess you have no problem with diversity initiatives then because sometimes increasing diversity for its own sake makes sense?
No, just the opposite. I think increasing diversity for its own sake, as I said at the outset, will lead us to injustice. Just like affirmative action does. I'm opposed to prejudging people based on the color of their skin.