Earlier quoted context omitted.
The US are also the major enabler of Israel's colonial expansion and ethnic cleansing of Palestinians. This was clearly expressed by Bin Laden himself as one of the motives behind the 9/11 attacks. > Were you thinking the US was just minding its own business and some bad guys came and attacked it As I remember, this was exactly the way the US explained 9/11: "they hate us for our freedom".
Yeah, he also justified it by citing the US's acceptance of homosexuality so maybe it's more complicated than that.
"As for the first question: Why are we fighting and opposing you? The answer is very simple:
Because you attacked us and continue to attack us."
And proceeds to list all the ways the US are militarily attacking and oppressing Muslims in the Middle East. It's a long list.
Homosexuality is mentioned only once in the letter, in the next section, where he criticises American society and morals in general and calls it to embrace Islam. This is explicitly an exhortation and not part of the reasons for the attacks (so probably intended as a diagnosis of the symptoms of a moral disease and the proposal of a cure - note that I'm not endorsing it, just explaining its function in the letter).