Why are the matchups in Clash of Clans so uneven at times?

How come we're in a war and our top guy is around level 86 or 87 and their top two guys are over level 100?

Their walls are way stronger and they have air defenses. When searching for an opponent does it eventually just give up and put you up against the closest opponent even if they're not close in comparison?

Clan wars are matched according to the strength of the members of the clan, not the best players in the clan. Strength is based on each member’s attacking power (troops, army camp capacity, spells and heroes) and defensive strength (defense buildings, walls, traps and heroes). Different layouts and base designs do not affect strength. The only way a member’s strength can be changed is if they upgrade their troops, defenses, spells, etc. If the opponent clan has 1 max TH10 and 49 TH1, and your clan is 50 TH7, your clan would probabily be ranked higher than them.