Why won't my crush follow me back on any social media, but he still flirts with me and acts like he really likes me in person?

My crush won't follow me back on Instagram but he let me follow him and I am confused because I looked it up and he follows litterly everyone in our group which is like 30 people except me! In school he still acts the same around me and still flirts with me all the time but u don't wanna ask him why because to me that sounds really annoying. But anyways he won't follow me on anything and on snapchat I added him and he won't add me back or he blocked me! But I saw him at school today and he flirted me as always and didn't act weird or anything at all! Someone please help lol I'm so confused
Why won't my crush follow me back on any social media, but he still flirts with me and acts like he really likes me in person?
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