If you aren’t exclusively attracted to the same sex don’t fucking call yourself gay.
Then stop using the terms gay marriage, gay rights, gay bars, gay pride, and gay community when you mean LGBT+ or same-sex. Stop saying “lesbian and gay organization” to refer to LGBT+ organizations – looking at you, pflag! If you don’t want gay to be an umbrella term, stop using it as one.
You can’t force the label gay on bi and pan people against our will and then complain when we use it. It doesn’t work like that.