I don't get it

I saw someone said to a ship "I am going to assume they were friends until (name) said they were in love" and it has me thinking, can you only identify love once you hear the words itself? Once you hear the phrase "I love you", or "I'm in love". This is why shipping has always been a double edged sword for me. Like I get it, you want them to be friends, sure. But if their only reason is because those characters said they're just friends, it will get me thinking: How can you not pick up anything more than just words? What about their gaze? Their actions? Their facial expressions? Their behavior? The tone of their voice when they mention that person or whenever they said their name? The subtleties. Everything. Words can mean everything and nothing at the same time, but actions only means everything. I'm sorry, this must be a bunch of nonsense. This is why I like people who notices these things about their ships, even though some people may say otherwise.