Why does he follow so many unknown girls on Instagram?

I like a guy and he likes me back. But he follows too many girls on Instagram. I don't understand the logic behind it. Those girls don't even follow him back.
When I confronted about it, he brushes it off.
What does this really mean? Does he really like me or see me as a mere option? Is he into many girls including me? Does he value me?
Why does he follow so many unknown girls on Instagram?
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