I feel like myself and others will/are having the same opinion towards people and robots as older people view same sex couples. It'll be interesting to see how people view these developments in 20 years and whether younger generations resent the older generations "robophobia". I could be making this up but it does prove our generational desires for progress only go so far.
I think you bring up a great point re: societal perceptions of human-robot sex in the 2020s-2030s. Younger generations will definitely be more accepting, however there will be a large cohort within our generation that are also accepting. I know I wouldn't care. Our generation is one of the most accepting and tolerant to ever live. Also one of the most educated. So there may not be an overwhelming amount of resistance to it.