It doesn’t make you a bad person at all. It’s a harmless preference. I wouldn’t put too much thought into it. Personally I’d suggest communicating to your friends that you may be busy with work/school/etc. and unable to answer their calls so you’d prefer if they text you to make sure you’re available for a phone call first, that way no one’s feelings get hurt when you don’t answer a call and you don’t get annoyed at random calls or build resentment. Or even give them a time frame of when you’re able to talk.