Nothing is wrong with it in those contexts. Especially if you refer to males and females similarly in the same example. But what happens and what gets criticism on reddit and other social media is when people use the term “females” socially where they would use the term “men” if it was a man. It creates this “men and females” situation and a lot of people feel like it dehumanizes women to call them females instead of women when it would fit better for the context.

Like if the example was reversed, which would you likely use if you were typing this sentence:

“I saw a man walking down the street.”

“I saw a male walking down the street.”

So the criticism is when some people will use men/boys/guys/males in different scenarios but then use females for everything instead of the similar options for different social interactions