i'm not sure about that whole veggies before fruit theory. i started both my kids on fruits first, and neither of them had any problems with veggies later on either (my little one will choose broccoli over a cookie every time!). but that's another thread....
as far as the pushing the food out with the tongue, and the whole "what are you feeding me???" facial expression... sounds a lot like how mine reacted when i first started feeding them solids. when babies push food out of their mouths with their tongues, they aren't doing it on purpose, that's just how they're used to eating (if you look at how they latch on to a bottle or breast, their tongue is sticking out a bit), so they have to learn how to keep their tongue in when they eat food. so with mine, i used the spoon and kind of blocked their tongues so they couldn't push the food out. i know it sounds weird, but try it, it works.
and definitely keep offering foods even if he doesn't seem to love them. i make a salad for both my girls at every dinner time. they both started out hating salad and i believe there were many nights when the salad was dumped onto the floor. but gradually they started picking at it, starting with the carrot sticks, then tomoatoes.... and now my almost 4 year old loves salad and will eat all of it when it's given to her. my almost 2 year old is still working on tomatoes and carrots....
anyway, don't give up! eventually he'll love it!
(ps - sweet potatoes are so WAY better tasting than carrots!)