1. "Gay and lesbian" is not synonymous with "LGBT." They are not the same thing. Queer and trans issues affect other people besides homosexuals. If you say "LGBT" and then use "lesbian and gay" interchangeably for the acronym, you look like someone who doesn't know what they are talking about.
2. Our marriages are not "gay." They are marriages.
3. Marriage equality (and any other LGBTQIA issue) does not only apply to gay people. Every time you talk about marriage law as if it only applies to gays, it erases people like me who are not gay and who still don't have access to fully equal relationships under the law.