Historically speaking, not all communists and communist-led governments have been anti-"LGBT". What many of them have been is anti-homosexual male. Albania is a good example of a country that was hostile to the homosexual male, but not hostile to the lesbian.

In the 'American' context, the (white) homosexual male rules over the LGBTQ community. It is the white homosexual male who sets the political agenda of the group, and this has been clear to radical queer critics of the 'gay rights' movement. This is why the trans-woman has been marginalized for so long, and 'gay marriage' has been pushed to the forefront. The white homosexual male in 'America' wants bourgeois respectability, and only tolerates the other identities in the alphabet-soup as is politically necessary.

As the user /u/__Zeik__ has said, it is actually quite normal for communists to be anti-gay. If you wanted to go down the "revisionist" road, you could make a strong argument being pro-gay is form of revisionism. Marx, Engels, Lenin, Stalin and Mao were all anti-homosexual. Engels most explicitly so, and Lenin indirectly. Almost all communist-led governments have been anti-homosexual, with basically the exception of modern day Cuba (though they were historically anti-homosexual too). Even most communist parties that have significant mass-support are anti-homosexual, such as the KKE in Greece.

Beyond all that, the greatest attacks on the male homosexual identity came from queer theorists. Queer Theory is basically a body of work that deconstructs the idea that the male homosexual is born that way. This work should be seriously studied by Marxist-Leninists. People are not born homosexuals, they are turned into them somehow. In fact, there was no such thing as a homosexual until fairly recently in history.

Some male homosexuals will deny this, and assert male homosexuals has always existed. This isn't true at all. It is true men have had sex with other men (and boys) for a very long time, but this doesn't mean anything. Even in today's world, the psychological and erotic motivations for men to have sex with other men are different. A good example is the bug-chaser, the homosexual that has an erotic fantasy about getting infected with HIV. In the erotic imagination of the bug-chaser, the object of desire is not the typical homosexual erotic fantasy object of a hyper-masculine male, it is a degenerate male homosexual with HIV, usually close to death and emaciated (and decidedly not masculine). That they have eroticized the male homosexual, rather than a mental image of a hyper-masculine man, has led many bug-chasers to say they're the 'true' homosexual. To a lesser degree, you see this in the bear/twink dynamic that exists in the male homosexual community. The bear is supposed to eroticize the effeminate homosexual, and the twink is just looking for the hyper-masculine male. The androphilic transwoman, the type of person who Western homosexuals will say countries like Iran are forcing to have a sex change, takes this the furthest, and refuses to even have any homosexual male partners, preferring to obtain sex exclusively from heterosexual men.

These are the types of people who rule the LGBTQ community in the West, and they are completely allied with imperialism and Zionism. The imperialists put them in charge, as opposed to bisexual men and women, or lesbians, or trans people, because the white male homosexual is the most opportunistic of the lot. The closeness of the male homosexual to the bourgeoisie is well known historically, and even in the earliest days of the development of the European labor aristocracy, you can see them maneuvering themselves into influential positions. This is partly why Marx and Engels hated them so much, and why the Bolsheviks associated them with fascism. They just looked at the rampant homosexuality in the early days of the Nazis, and put two and two together.