"We are all equally sinners" and "God loves everyone equally" are standard defenses of people who claim their stances around the sin of homosexuality are not oppressive. They are correct in that those two statements are not oppressive and lay the ground work for a non oppressive understanding of both sin and love. Unfortunately a firm foundation does not always a plum house build. The next step one must look at is the material repercussion of sin and the theological/pastoral relationship between an individual and sin.
The law codes of Leviticus and Deuteronomy are just, exceptionally harsh, but just. There is a certain level of sin1 and there is a certain level of punishment. If you commit adultery, masturbate, are involved in a male on male rape, you should be put to death. Now this is a horrific material repercussion, the loss of life, but it is one applied equally to a category of sins, mortal sins. I might disagree, and I do, with categorizing these things as mortal sins or even sins of the same level... but I can recognize the system as internally just. There is a certain level of sin, mortal sin, and all mortal sin has the same material punishment, death. I cannot say that about how many theologies of sin today approach mortal sins.
In a culture that had material justice around mortal sin we would not be able to differentiate between adulterers, masturbaters, and those who participate in same sex acts.2 I think we can all attest to the fact that the cultural implications for a male who acknowledges actual acts of masturbation is markedly different from the cultural implications for a male who admits even the temptation to partake in a same sex act. The same can be said for the implications of stating one or the other in a Roman Catholic confessional booth.3 The reality being that Christian traditions that consider all mortal sins equal do not treat them as equal nor do they seek for society to treat them equally. This lack of internal justice shows that while a church may say "we are all equally sinners" it does not mean that the church "treats all sins, even those of the same level in tradition, as equal". This cultural and pastoral privileging is the first means of oppression.
The next question is wether or not all selves are treated equally in the relationship between self, God, and Church. Is the self marked by homosexuality equal to the self marked by heterosexuality? Selves marked by homosexuality are not allowed, in many traditions, to be chaste only celibate. Chastity is the capacity to discern fully the use of one's sexuality and then live out that discernment. If a tradition refuses selves marked by homosexuality to be chaste then the church is seeking to block the relationship between those selves and God in a way they are not selves marked by heterosexuality. This is an inherent privileging of any self marked by heterosexuality over selves marked by homosexuality.
The way these theologies do this is by refusing to acknowledge the concept of sexuality in any way shape or form and only recognizing sexual activity. The question is never about the emotional, physical, spiritual, or mental well being of the individual involved but only about the specific sexual acts involved. The only sexual act that can be emotionally, physically, spiritually, or mentally beneficial is procreative sex in the context of marriage. Any person who puts forward that their emotional, physical, spiritual or mental well being is benefited by any other form of sexual activity is automatically invalidated. This individual is, by default, incapable of having a proper relationship with God and their conscious is inherently flawed until such time as they deny such benefit and recognize they were under the sway of satanic forces. This automatic invalidation of personal conscious and a person’s capacity to understand their own relationship with God is how “God loves us all equally” must be met with “and we all have equal ability to love God” or it can quickly be a phrase of prejudice.
So here is the end of it. If your theology maintains systems where homosexual “mortal sins” are treated differently from other “mortal sins” and dictates that homosexual individuals are inherently flawed in their ability to relate to God and maintain their own conscious... then your theology is prejudiced against the LGBTQ community. You can hold prejudicial theologies and maintain prejudicial systems and fully believe that “all sins are equal” and “God loves all equally”. These statements do not absolve one from being an instrument of oppression. They just don’t.