It's not bigotry. It's blindingly obvious. And I know this from personal experience. My mum was a nurse in the 70s and 80s (worked in several old people's homes) and used to come with sone shocking stories.
Go ask a 70 year old if they'd be happy with a black or gay Prime Minister and report their answers back to AB.
In fact, don't bother - we all know what they'd say.
There are loads of genuinely fair-minded, open and accepting elderly, but taken as a whole, they are FAR more bigoted than, say, a similar group taken from the same socio-economic group, but under 40.