I am gay and work at Walmart and was wondering if this is discrimination?

Lots of employees at walmart put stickers on their name tags. One of my friends there has a price "$5000 per ft" others have smiley faces or other random stickers. I put a small sticker on my name tag saying "gay & proud" and after having it on one day I was called out back and "asked" to take it off. When I said other people have stickers, they said they try to not allow that. Even though people there have had stickers for months and they talked to me after only one day. Is this as clear discrimination as it feels like or should I drop this