In my understanding of culture, native born American, to tell someone you “love” them implies a great deal of intimacy and trust. The word implies something that must be built over time and is unique and lasting. It often has an implication of confirmation after you’ve dated someone long enough to re-affirm that you want an even more serious relationship.
There are lots of variations on that theme, but the point is that when it’s offered without the backing of a safe and intimate, developed relationship, it reads more like “I am obsessed with you”. It can suggest a failure to be in touch with your own emotions and/or a gigantic failure to see and appreciate the recipient as an individual. An obsession with surface appearance or even the speaker’s own fantasy about the recipient.
“How can you love me? We barely know one another. I don’t know that I currently trust you enough to have even shown the parts of me you could claim to love. You must love your own conception of me and I don’t trust that.”
That said, variations on “I like you” are basically the same sort of relationship-opening confession and are often welcome. It’s considered normal to “like” someone’s public and non-intimate social identity enough to want to get to know them more (through more intimate dating).
The other big confession to note is “can we be exclusive/go steady?” This one implies you like someone enough that you’d prefer if you and they focus exclusively on this relationship. Its rejection may end the relationship (or may not, it can be done lightly) and usually comes between “like” and “love”, if it comes at all. Not everyone practices dating non-exclusively.