Should I mind about our height difference?

My friends are quite perfectionists'--in a very bad way. Just last week when I introduced to them my new gf, the woman I met in a filipina bride tours, they gave me a smirking reaction. After that day, I confronted them why they've been very cold to my girlfriend; they said we're not compatible, that I am way too tall for her. I was taken aback. And that when I realized about our height difference. My gf is only 5 ft tall, while I'm 6'5 ft tall. Is this really a concern? I decided not to think about it much but my friends are persuasive in putting an end to my relationship with my gf. Should I mind about their side? I can't just break up with my girlfriend!