Patriotism doesn't have to be about thinking your country is perfect. It can be about wanting your country to be better. The US is a massive place with an incredible variety of people - there's tons of things that suck but there's tons of things that you can appreciate to.
If someone doesn't want to celebrate it, I'm fine with that. I can understand why someone might not want to, and it's their choice to do as they wish.
As for me though? Well, I work today, and I'm not really into fireworks and partying...but I'm an optimistic who thinks America has the potential to be an awesome place. I'll show my support through memes.