How do Holocaust deniers explain the gypsies, LGBT community, and other minorities Hitler considered undesirable?

Either they don't or they minimise the numbers by pretending many of them were criminals.

btw being a lesbian was not specifically an offence, being a gay man was.

Holocaust deniers seldom deny that ANYBODY was killed. They just drone on about how all these people were being kept in camps for their own protection from the indignant clean-living Germans, but because they were all dirty and imported their own lice,  it's not surprising if they contracted typhus and died.

These groups are considered undesirable to all English-speaking governments. Founding fathers from the United States hated these groups as well and came here to practice other forms of Christianity. This country was made for that—not anything illegal or against the Bible.