From where I'm sitting, Americans can and do associate freely in all aspects of our lives. Groups may clash with other groups, but for the very large part, we are pretty unrestricted.
Not really. One tiny example among many in the US:- clubs which are exclusive, such as allowing only male membership are frowned upon heavily in the US and are constantly targetted. In New York, such clubs were banned by law as regards being exclusive.
While some people here might foolishly find the existence of male-only clubs offensive, the opposite is the case. Just as women should have the right to set up women-only clubs, so should men. That is only logical.
I can give an example of such from my own British side of the family. My father was once given a letter from his first wife asking for a divorce, he then happily obliged her by seeking one in the courts(as she was a gold-digger etc.). His first wife then changed her mind and asked her lawyer for advice. Her lawyer told her that if she wanted to continue the marriage all she had to do was meet her husband, even if only for a few seconds, and the court would recognise her as having reunited with her husband according to the law, thus voiding the divorce(this was the 1950s, after all). My father duly fled to a gentleman's club in London in which he was a member and hid there. She knew where he had fled and tried to get in but was refused entry because it was a male-only club at the time and banned female visitors. My father then had to flee abroad to avoid his first wife, afterwards, and , thankfully, she then married an American admiral, so he was rid of her. The point being that without the freedom of association exercised by this club, his life would have been ruined.
What I'm curious about is where your views come from. Perhaps international opinion skews the news in the direction of sensationalism (because it sells). The US is not all Ferguson and Florida. It's all just me and roughly one-third of a billion people just like me, but different.
I get most of my views about the US from Americans who complain online all over the place all the time about how their freedoms are being restricted. Much like Europeans complain, my sole point was that neither Americans nor Europeans have unrestricted freedoms and actually live in rather totalitarian societies, it is merely that Americans lack some freedoms that Europeans have , and vice-versa.