Wearing my super-hypothetical-since-I-am-privileged-and-this-doesn't-actually-affect-me hat, if I were the adopted parent of a child in a same-sex couple, or were traveling with my spouse in a same-sex couple, and I thought there was any real risk of having to go to a hospital with either an incapacitated spouse or a child, I would be much more worried about coming to the U.S. than to Singapore.
Why? There have been actual, recent, documented cases of hospital personnel violating the law to deprive people of their rights, and we have no assurance that this couldn't still happen. There are documented cases of this happening in Miami and Nevada as recently as 2013. Given the current political backlash over same sex marriage, I suspect the risk is higher now than it was in 2013.
I haven't been able to locate any documented cases of this happening in Singapore. What I've read thus far about Singapore suggests that things are getting better there, not worse. This doesn't mean there is no risk of falling afoul of a fanatic, of course. But clearly the odds of that are higher in the U.S, despite some very sincere and concerted effort on the part of the U.S. government right up to the office of the president to prevent recurrences.