In many (although not all) areas of the country, efforts are being made, both socially and politically, to keep homosexuals and homosexuality out of the public spotlight and to stigmatize the practice. These efforts take many forms and result in very real limitations on the ability of homosexuals to express themselves, plan for the future, feel secure in their employment, and otherwise lead "normal" lives. The most chilling effect is on young people, many of whom feel so stigmatized by their families and their peers that they have to lie for years about what they feel, or worse, take their own lives.
No, gays are not being rounded up, imprisoned, executed, or experimented on. But I don't think those are the sole hallmarks of oppression.