You had asked if/.why someone might think your shots are snapshots or artistic. To me, artistic expression comes in many forms and even snapshots can be considered art.
I think that people are saying that because of their lack of ability to categorize your photos as “STRONGLY ARTISTIC.”
Now, ask yourself this question, what is your reason for taking a photo? If it’s to capture the moment, or memory, then it is less artistic and more a memory photo. If your reason for taking the photo is artistic then it is art.
Finally, you need to train your artistic eye. It comes from looking at photos from other people and deciding what you like and what you don’t like about them. You should also start to chose what genre you want to work on – be it portraits, nature, architecture, etc. Then go out and find every resource on the internet you can about that genre – look at hundreds of photos in the genre and train your eye to figure out what works and what doesn’t.