Dunno, it doesn’t fit Zarya’s style to deliberately attack a peaceful city JUST because they live in harmony with the omnics. Her reasons for omnic hate are much more personal than that and she’s smart enough to not be manipulated to that kind of extent. I mean, a random unprovoked attack against a city/country (what is numbani anyway) would turn them against Russia and zarya would not want that, they have enough problems on their own.
Trashing security bots for the sake of trashing robots just does not fit her personality, she has a big distaste for Omnics and doesn’t trust any but omnics would have to provoke or threathen her to instigate such a response, like how she says “im keeping an eye on you omnic” to zen if they’re on the same team instead of some hatefull speech. And it’s not russia’s territory, she is needed elsewhere, she might even refuse to go if asked because she is patriotic and knows russia needs her more than ever where it matters, in the frontlines keeping omnics at bay. Not random airports trashing bots and stealing gauntlets.
Remember, she left her weight lifting career voluntarily to defend her country. Attacking another nation unprovoked would go against this ideology. She might not even give rat’s !@# about what happens outside Russia anyway if it doesn’t concern her country, her motives lie entirely in being able to protect the people she loves and her countrymen. She’d be a big hypocrite if she instigated war against those who support omnics.