(Spoilers)
After some thought, discussion, and reading, I actually found a contradiction in Flowey's words. There is some evidence that actually gives Flowey the possibility of having some of his SOUL. Here's his quote:
I soon realized I didn't feel ANYTHING about ANYONE. My compassion had disappeared! And believe me, it's not like I wasn't trying. I wasted weeks with that stupid king, vainly hoping I would feel something. But it became too much for me. I ran away from home. Eventually, I reached the RUINS. Inside I found HER, [Player]. I thought of all people, SHE could make me feel whole again. ... She failed. Ha ha...
I can't believe I