I also thought this and weaned my kids on exactly what I and my partner were eating. Even steak pre-teeth! - they sucked all the juices out with apparent relish 😂
Then with eldest they hit a wall at about 3 and started refusing things - more and more foods that they used to eat happily and then wouldn't. And then became fussy about foods 'touching' so mixed up meals like pasta dishes, pies etc became harder. Then all fish apart from fish fingers went by the wayside (used to happily tuck into salmon and trout). We didn't do anything to prompt this, it just began. With my youngest, same thing happened but a bit earlier (perhaps as she saw her sister refusing).
In both cases initially we just kept on giving them what we ate - nothing getting eaten, already skinny eldest starting to look ill (youngest still breastfed so kept her chunk up better), other half actually putting on weight eating up all their leftovers (he can't stand wasted food). So then we started making 'what we're having'-lite - so the pasta and the meat and the vegetables of bolognaise but separated out on the plate, not mixed in the sauce for example - but still they'd usually eat all the veg and most of the carbs and hardly touch their protein. And then started hating different parts of the same thing, or different versions of the same thing - so my eldest now hates 'good' sausages, preferring the lurid pink Richmond types, my youngest won't touch them and demands 'Taste The Difference' type high meat content ones - and both of them refuse to eat 'the skin' so sit there peeling their sausages at table :( My eldest loves eggs and will eat them in any form, youngest won't touch them at any price. Basically it became bloody ridiculous and I was cooking three different meals at the same time only for most of it not to be eaten anyway.
Literally the ONLY meal they will both just sit down and EAT as it comes is roast dinner. So now we have that every bloody Sunday, and we were never a 'Sunday roast' kind of family!
Now they both get their main meal in the week at nursery/school, so I just give them a sandwich and salad when they get in and we only have the torture of trying to get a proper meal into them 3 nights a week. What goes on their plates often doesn't look much like what goes on ours; but we always eat together at the table, and they always eat all their veg (very boring plain steamed broccoli, green beans, carrots, peas, and 'cutted up' cucumber and peppers are always acceptable) and they have to have a hand-size portion of some sort of protein, even if its just a couple of fish fingers, a spoon or two of tinned tuna, a hardboiled egg, a piece of cheese or a slice of ham.
I could have just stuck to my guns I suppose but then I'd have a very skinny eldest and a very fat partner 😂I figure they'll grow out of it, They're adequately nourished, and I don't want to turn food into a daily battle-ground just so as I can be smug in Cafe Rouge while my little ones tuck in to their Spaghetti Puttanesca.
Certainly it has nothing to do with weaning them on bland food or thinking children 'shouldn't' have foods with flavour! It is well-documented kids get fussy at around 2/3, and it is hypothesized this has an evolutionary function as it is about the age kids are capable of finding and eating food on their own so it makes sense for nature to arrange matters so that if while foraging in a bush they find some unfamiliar berries the instinct is to go "don't know what that is, yuck no" rather than "mmm yummy" as they scarf down the deadly nightshade. My little brother ate olives happily until he was 2 then turned up his nose at anything green until he was nearly out of primary school ("I'm not eating that it's a leaf!"). It's just a thing. Parents can fight it, roll with it or get creative (or a combination of the three).
I'm sure your olive-eating little darlings have some childlike faults as well; let us hope your friends are a bit less judgmental :)