I think it is undoubtable that future socialist states will have better LGBT rights (whereas capitalists only bother if it can get them extra profits, which is why some modern movies have shallow LGBT representation) because being LGBT is not an ideology, but a science that future socialist states (assuming they adhere to scientific socialism) must take into account if they are to apply their scientific socialism to all aspects. LGBT workers are also a significant group socialist countries ought to take into account when unifying the working class into a fist to smash the old system (foregoing that would just risk a failed revolution on account of alienating a subsection of workers for little practical reasoning).
As fighters against oppression, the communists must not merely focus on fighting on the side of the proletariat, but the oppressed stratum of non-economic groups: queer people, those with physical or mental disabilities, ethnic minorities, etc. I find any reactionary communist groups unwilling to fight for oppression in spheres outside of the class struggle likely to fail due to pushing these oppressed groups into the hands of manipulative bourgeoisie willing to "support" them slightly more than these reactionaries would (they hardly care for these oppressed groups, but they are willing to drum up discontent and offer concessions if it means destroying the communists; afterwards, they are free to cut off the concessions because any threat to their bourgeois state is gone).
Sorry if this was a shallow explanation because I was trying not to speak too much about something while still not having much theory in my brain.
Note: Someone used a term I made up! I hope you liked it! I am happy hehe