I really don't see any problem with this. It was clearly meant as a joke. Does anyone seriously believe that Hammond thinks any man who eats ice cream must be a homosexual? It's a joke. A distasteful one maybe, but that's the thing with humour - different people find different things funny. No subject is inherently funny or unfunny.
People get offended far too easily. Who in their right mind is surprised that The Grand Tour uses borderline-offensive humour, stereotypical humour and the like? It's hardly a surprise that Clarkson, Hammond and May continue to use the same format, same sense of humour as they used on Top Gear. People can't even use the excuse that "it was just on telly WAAAAAAH" or "I paid for this with my licence fee WAAAAAAH." To watch this programme, you have to make a deliberate decision to download it. Nobody is forced to pay for Amazon Prime if they don't find it good value.
What I do find offensive is the knee-jerk, hysterical reaction, the assumption that anyone who enjoys The Grand Tour must be a neanderthal, a pathetic loser. Dismissing the viewers in this way is just as offensive as making a joke about ice cream being "gay"!
Different people find different things funny. Nobody has an entirely "right" or entirely "wrong" sense of humour. There is plenty of "comedy" on TV that I find highly offensive (Michael McIntyre or Mrs Brown's Boys for example), but I have to accept that there are people who find it entertaining.
We are not all the same, and the people who have their fingers on the trigger waiting for the next opportunity to have a pop at Clarkson, Hammond or May (probably with the next episode!) should remember that diversity means accepting other people have the right to be different to you.