I agree that men also get flack for doing activities associated with women, my answer to the original comment is disagreeing with the double standard part. I think it's bad both ways and therefore not a double standard

Also, it's not just targeted at people perceived as "other" in many of these traditionally masculine realms.

Often, it seems like so many of these men see patronizing and second guessing as the only ways to establish and defend their own credibility on their given subject. It's not just the "oh it's a woman/someone who doesn't look the part...I bet they don't know what they're doing" factor, it's also that they're a product of the culture that tells them that the most important thing is that they're perceived as more knowledgeable than anyone else, and that the only way to establish that is to have their own opinions and views on every subject in the field, and then aggressively defend and promote those views while dismissing, undermining, and discouraging any views that conflict with theirs...or the people who hold those views.

And it's not just big picture "world view" type stuff. It's crap like, "which brand makes the best widget in your hobby?". If they're a "brand red" guy, they feel the need to not only let everyone know that they like brand red...they have to let everyone know that brand red is the best, and that it's objective, and that if you prefer brand blue, you're just a clueless newbie who hasn't learned yet. If you like brand green, well you've just been taken in by their marketing. And if you're one of those brand orange people, well you know what they say about those people...

I can never be sure, I'm not inside their heads, but I don't remember ever seeing this behavior directed at my husband or dad when tagging along with them in similar situations.