Why does he still text if he's not interested?

Read the pattern before the message. A man who is interested tends to ask questions that need an answer, suggest a time and place, and follow up when a plan falls through. A man who has cooled but still wants a fallback usually sends things that don't demand anything back: a link, a photo of something he thought you'd find funny, a generic check-in with no question attached. The text might be pleasant, and that is the point. It keeps the door ajar without walking through it.

Notice the gaps too. If he goes four or five days between messages and then sends something light, the rhythm tells you more than the words do. Also notice whether he ever moves toward a real plan or only toward more texting. Texting is cheap, and a man who only texts is often telling you how much he is willing to spend on you.

Two kinds of reply tend to fit this situation. One is the short, warm reply that answers what he sent and stops there. It acknowledges the text, adds one small detail about your own day, and does not end with a question that asks him to keep going. It's for when you're fine with the thread staying light and want to see whether he moves. You can tell a draft is this kind when it is shorter than his message or about the same length, and when it doesn't ask him anything he would need to think about. It should leave out any mention of how often he texts or what it means.

The other kind is the reply that sets the terms. It is for when you want more than the thread can give. It is still warm, but it names one concrete thing you'd like, such as a specific plan or a clear answer about where things stand. You can tell a draft is this kind because it asks for something he has to actually decide on. It should leave out hints, sarcasm, and any sentence that sounds like a warning. The aim is to make the next move his, in plain words, not to win an argument about how he has been acting.

Timing carries a lot of signal here. A reply sent late at night or in the middle of a long gap reads as either bored or hurt, and both give him more to work with than you want. Wait until your day is actually full, so the reply comes from a normal place. A few hours is usually enough, and waiting until the next day is often better if the text didn't need an instant answer.

If he doesn't reply to your message, leave it there for at least two or three days before sending anything else. A second message that just says "hey?" tends to make the silence about you. If you want to close things out, one short final message is enough, and it does not need to explain anything. After that, stop initiating. If he comes back with a real plan, you can decide then. If he only sends another low-effort text after a few weeks, you already have your answer about the thread.