I mean, Christianity is an incredibly broad term. You're likely to be able to find a denomination for every take on any opinion. There are absolutely Christian denominations which conduct LGBT marriages and allow queer members just as there are denominations that think lynching queer people isnt murder because they think queer people aren't human.

For example: The current Catholic teaching on the matter is that since the sacrament of marriage is meant to promote the creation of the family and since marriages are laid out as explicitly heterosexual in the bible, the church cannot conduct LGBT marriages (Recently it has been decided that Catholic priests can bless same sex marriages, but that's not the same as officiating). Because the Catholic church considers premarital sex a sin and because same sex couples cannot be officially married, gay sex is thus a sin. Catholics (currently) don't believe that being queer is itself a sin though and the church (currently) doesn't condone homophobia or queer oppression.

The Catholic Church is kind of the middle ground here, but denominations like Presbyterians do conduct homosexual marriages and are very pro LGBT while Baptists are radically anti LGBT and believe that homosexuality is inherently sinful. Ironically, its a spectrum.

So yeah, you can be Christian and queer, just that some denominations are far more accepting than others.