Not sure I'm worried about a small "estrogen" enhancement. If it were a problem for men then half of Japan would be in deep doo doo. Besides Natto, they are big consumers of soy sauce and miso...
Natto is fermented (natural fermentation) which enhances your gut biome (probiotics naturally) and also is a good source for nattokinase (which I take in supplement form), which is good for your blood and keeping it clean of clots. There are supposedly a lot of health benefits for it and the stupid thing is I'd probably like it if I have it a good chance.
It's a mental thing. Like beets. Beets are one of the foods I don't eat. Even other things I wouldn't choose at a buffet, like okra, or lima beans, or almost any food, I'll eat if its placed before me. But not beets. And for now, not natto.