You're probably using the botanical term 'fruit', while the GP was using the culinary term 'fruit'. Olives are not fruit in the culinary sense (no one puts olives in a fruit salad).
I'm pretty sure this is wrong. No one puts lychees in a fruit salad either. There are a couple of things going on:
1. Lychees and fruit salads come from two different cultures, so there's no real way for lychees to be part of fruit salads. The groups "people who make fruit salads" and "people who eat lychees" have negligible intersection.
2. "Fruit salad" is a word that refers to something in particular. There's no obligation for fruit salad to include all fruits, and in fact it never does.
But if you ask people what olives are, they'll tell you they are a fruit.
And people put avocados in fruit salad all the time, despite the fact that, like olives, they are a nonsweet fatty fruit.
But that's not evidence that chicken isn't considered "meat". It is.
There are two separate points here: my point was specifically that culinary and botanical categories for the word fruit do not overlap - there are botanical fruit that few people around here would consume as culinary fruit, such as olives and cumin. There may be culinary fruit that are not botanically fruit (for example, some may consider rhubarb stalk 'fruit').
Even if you are right that when asked what olives are people would say 'fruit' (I believe you'd get a variety of responses, with some calling them legumes or even spices), that still doesn't mean that people think of them as fruit. If you ask someone to pick up some fruit from the market, they won't come back with olives.
Your point is also correct, in that the culinary fruit category is culturally specific, and different cultures may regard different foods as 'fruit'. I doubt there is any culture where culinary fruit is perfectly matched with botanical fruit.