so everyone loves the native americans as a defensive civ but there UB doesnt benefit there UU so is everyone just illogical?
Everyone loves NA? They're certainly decent/solid, but I am hardly seeing this love you describe.
Their UB is much more *consistent* than the dun (dun relies greatly on hills, experience for archery does not) and much more commonly built (monument is used for border pops often, walls less so other than on borders). Their UU is also more consistent, and although it nerfs the axe rush it gives early tech flexibility vs barbs and really owns enemy melee rushes...and not just on hills.
What puts totem pole over dun (though totem pole is a pretty average UB too, at best) is that both its offensive and defensive capabilities ARE consistent. Protective crossbows have some teeth, and NA can stack up drill or counter promos on them like nothing. Protective longbows with CG III are obviously a pain, but NA gets that on its archers too and it really changes the viability of rushing them (even on flatland cities, swords struggle). They last about the same time (only viable/meaningful unit celts get with guerilla I off of the dun that totem doesn't get is muskets), but one is helpful regardless of terrain and applies the bonus to flexible XP instead of a promo that is fairly dodgy without lots of hills.
I'm not saying the UU/UB have synergy for NA though. Just calling out the ridiculousness of an earlier poster claiming the celts DO have UU/UB synergy, which is nonsense. Keshik/Ger is synergy. Impi/Ikhanda is synergy. A defensive structure that does not apply its bonus to the UU regardless of its existence is not synergy. To rub salt in that "synergy" argument's wounds, the only units the ger helps are not really ideal for keeping gallics safe from counter units, aside from on hills where gallics dominate anyway.
They have absolutely no weakness to any units during that time period
Actually, they have a glaring weakness. The AI just won't expose it because it's terrible.
Horse archers are less
(even without AI bonuses), can also reach a 2nd promotion easily, are available earlier, ignore ALL of those first strikes, and have a withdraw chance. Even with drill II + formation, a longbow pushing into enemy territory on flatland will see HA at 7.2 str vs 6(.25)+6= 7.5. Barely better odds, before factoring withdraw chances, ANY collateral initiative at all (AI doesn't use that well though), or the flanking damage this will cause to any siege you bring. Comically, if opposing swords can get cover they'll cause problems too.
You DO need siege, too. Longbows struggle vs archers defending cities, let alone things like axes or swords with any amount of 20-40% culture, or 50% walls, or fortify. And of course, the dreaded noobiphants can always cause a beatdown too, but they're overpowered anyway
.
Also note that ANY protective civ can produce drill III longbows by simply swapping into vassalage, which you can always do if you have the ability to build them. NA simply has 3 extra xp towards drill IV and while that is definitely useful, it's not spectacular unless you're playing churchill of NA
.