I would say "lifestyle" is only a term that should be used in relation to homosexuality for us who are Bi-sexual. For me, choosing to be in a heterosexual marriage even though I am also equally attracted to females makes my choice a lifestyle choice. However if broken down by definition it really applies to all sexualities equally.
The actual definition of "Lifestyle choice" is a choice a person makes about how to live and behave, according to their attitudes, tastes, and values. So with that said a gay person is in a sense choosing their lifestyle by not denying what they are. Just the same a heterosexual person is making a lifestyle choice by not going against what feels right to them and being gay.
Like it or not sexuality is a choice. You can choose to hate the person you are with. You can choose to be in a relationship with someone you are not attracted to. Should you? Of course not, but it is your choice.
A common trend among SOME believers is to ignore their own "lifestyle choices" and to degrade others. We all make lifestyle choices about our sexuality. Some choose to say it like it's a bad thing. It might be, but likely a gay person's choice to seek out another gay partner is no different than a heterosexual person seeking out another heterosexual partner.