"Taking a knee is still a means of showing respect."

No, it's not.  It's just the opposite for this context.  Which is precisely why they're doing it, and precisely why it's getting the attention that it is.  

Kneeling in church is a sign of respect.  Maybe you're confusing that with this.  But in the context of the national anthem, kneeling instead of standing is DISRESPECT.  There's no way around that.