I don't think it's a no-brainer.
Some women, you text them the next day (not talking about blowing her up - talking about ONE text) and they categorize you as a clinger or low-value and they lose interest. Others, you wait three days and they decide you are using them sex. So what's the magic formula? Many men wait 3+ days because of bad experiences reaching out the next day. As a woman, I'm sure you would love a guy to reach out the next day because you get that validation, confirmation, and comfort of feeling that he is interested in more than just sex, but that is quite different from what you respond to in terms of attraction. Meaning: Many people want what they can't have, or can just barely have. If someone makes it easy, you likely lose interest. Women want to be comfortable, yet respond to sexual tension.
So I don't think it's a no-brainer that it's a man's obligation to text after sex, and he should do so the next day, otherwise he's made a mistake and the girl is going to think he's using her for sex. She is perfectly capable of texting as well. Rather than make assumptions of his intentions, if she wants to know, why doesn't she reach out first? Is it because she doesn't want to reach out and risk being rejected? Doesn't a man face this same situation when he reaches out after sex? Again, why is the duty on the man here?