Yeah, really. It's part of Riot's whole "we can't marginalise anyone", but the whole problem with not making tanks unkillable is that they're simply butter to carries that have the proper penetration items.
Giving almost 50% armor penetration to an AD Carry is annoying as hell. The tank just gets kited out in a fight, and they're unable to properly do their job. I'd suggest tuning it down to 30%, same with magic penetration. There's nothing more demoralising than finding out the item you're building to defend yourself against a damage type is already going to be worthless when a carry already has either Void Staff or a Last Whisper item.