Defensive AD items give good offensive capabilities and vice versa

I had to lane against a Jinx top earlier as Akali. Despite the whole ranged vs melee lane thing, as well as repeated ganks by Lee Sin, I did pretty well. Lived until 6, and managed to zone her off of so much cs.

But then Jinx recalled and bought a hexdrinker. Okay. No biggie. I was ahead and could still fight her if she overstepped.

Then her support and jungler camped me, and eventually dove me, killing me and taking my tower. With that gold, she was able to finish a pd.

Two defensive items. I thought I would still be able to bully her because she was squishy, and two defensive items normally means you should be lacking damage. Turns out with just those items, she could withstand my burst, while still being able deal scary amounts of damage.

Then she got the bloodthirster. Such a shit build for an ADC, but it worked apparently because PD in itself is a good defensive AND offensive option for ADCs. BT is one of the greater AD threats, but it also provides a hefty shield too. Hexdrinker just fucks anything AP.

Why do AD champs (ADCs in particular) get defensive items that give good offensive stats, and vice versa :/

Also I'm sick of this whole ADC in solo lanes thing. It's not fun to play against.

That said, I have been an abuser of Lucian mid, and have recently even been playing Xayah mid because it's just too easy.