OP, don’t feel compelled to justify your question to everyone on here. I let that happen to myself on another thread this week, and the whole discussion got sidetracked. Obviously there are other paths you could choose, but you are asking about this one here, which is fine.
I think it’s great that you have a plan. You should know that plans sometimes change, but it is good to have a plan of some sort. Just be aware that getting into med school is very difficult. So the advice you are getting is sound to pick a major that will leave you with a backup career you would enjoy if you decide med school isn’t for you, or if the med schools make that decision for you.
Also good advice to be open about what you want to specialize in. I think most of my friends who are doctors started med school with a different specialty in mind than the one they ended up in. One of their rotations just “clicked” and they decided to go that route. Or the opposite happens, one friend was planning on being an OB/GYN since I knew her in high school. After her rotation, she told me no way was she staring at THAT for the next 30 years, she switched to internal med to get more variety.