There’s a valuable point here, though it’s not so black and white. There are circumstances where someone might appear to not be into you but actually is. For example, maybe someone has anxiety or is currently dealing with an illness or personal issue. There’s also situations where someone isn’t into you yet because they don’t know you well enough.
The takeaway here is that if someone knows you reasonably well, and they’ve had several opportunities to take you up on an offer — all of which were rejected — then the excuses probably do translate into “I’m not into you”. And for those with personal issues preventing them from acting on their interest, at the end of the day, they’re not with you, so does it matter?
It can help to evaluate all of our relationships from the lense of who is really into us. Get really clear about who is always there for you and doesn’t go away even after so many years, arguments, and circumstances. Those are the people who are definitely into you. The others? Be careful how much time you invest in them, especially if they invest zero into you.