I'm going to risk a sensible answer 
OP, yes perhaps some people are jealous. But others are probably struggling and seeing you with what appears to be a much easier life, probably reminds them of how hard things are for them.
DH are comfortably off. Not mega rich but financially secure. A lot of comments that may sound like jealousy are, on another level, statements of fact.
e.g.
Its OK for you, if you don't like the local schools you can just go private - This is true, for various reasons, we chose private over the local schools - we had a choice, most people don't.
Its OK for you, you'd be alright if you lost your job - This is true. We have more than one mortgage free property and sufficient savings to bridge the next 20 years to retirement if we absolutely had to. It would be a reduced standard of living but nothing to complain about.
A lot of people are frightened right now about their futures and the futures of their children so I can understand why those fears get directed at people who seem to be insulated from these worries.
Note - I do get slightly twitchy about the urban 4x4 in Central London whose owners would have the vapours if they got mud on it.