Some people don't like a particular company because of it's business practices, and some always root for the underdog. And that's reasons for the opposite of your question, why some people prefer AMD
Intel has a higher IPC, a more mature and stable platform, and gives more performance in games. For many years AMD was not even in the running performance wise. Ryzen has changed all that and is now a very good alternative but intel is still ahead in IPC and gaming performance and therefore still the preferred choice for many people.
I switched to AMD when the Athlons were the performance kings, and switched back to intel when the core family started dominating. A lot of people are like that, we just go with whatever works better. It's a bit harder right now because which is better depends on your own criteria, Ryzen is tempting but the high end 8 series intel chips are as well.