It's fair to say he had no
direct link to IS/Da'ish. Just like someone today could claim to be in agreement with Hitler or the Nazi party, Omar Mateen seemed to be really ignorant about Islam and Islamists.
Omar Mateen had a history of making claims about ties to Hizballah (a Shi'a group) and Al-Qaeda (a Sunni group). When the FBI interviewed him,
Mateen didn't seem to understand the difference between the two sects of Islam.
The father seems odd when he speaks english. I haven't seen a translation of the videos (which are in Dari- the universal language in Afghanistan for the middle class) but just the idea that he's on a US-based Afghani news show (which apparently he paid to be on) promoting himself as a candidate for president of Afghanistan is an indicator that his brain doesn't quite work like the typical person.
The pressure is something common to all of the Abrahamic religions. The societal pressure is not too different from pressures in the US as recent as the 1940-1950s when homosexuality was illegal and considered a psychological disorder.
What differs in a lot of middle eastern countries is a familial and tribal pressure to marry and produce children. Homosexual sex is not uncommon or particularly rare, nor is male prostitution. It's living a homosexual lifestyle or behaving in an overly feminine way that prompts the backlash.
That backlash is from the society at large, as much or more than from Islam.
Think of it this way- for most of the 20th century, there were many gay men in the US who married and had families but conducted their same-sex relationships on the down-low. It wasn't until gay men started demanding the ability to have openly and exclusively gay relationships that the society backlash reached a fever pitch (between 1970 and well into the Bush years through 2004).
For gay men who live in countries like Iraq and Afghanistan and areas controlled by Da'ish, there's constant fear of being discovered. Being caught can result in arrest by the state, public beatings (by the state), hanging/stoning (by the state or by mobs) or being lynched (by mobs).
If the people on the other gay board are talking about pressure and they live in the West, the pressure is psychological and it's more about getting married, having children and covering up what they do on the side.
Some of the speculation that went on last week about Omar Mateen being gay or closeted doesn't seem to be panning out- the FBI is doubtful and the hard evidence of any homosexual conduct by Mateen hasn't surfaced in all of the information that has been out there in the past week.