Twitch should be allowed to decimate teams from 850 range

3 crit items is late game for an ADC. Remember, ADCs build really expensive items. They were made like 200 gold cheaper each because of the ADC in 2017 lul meme. Any crit ADC was completely useless until they had their full build because their damage items were so expensive that they wouldn't get any survivability until later and would then die at the start of every teamfight no matter what.

Also, Twitch is kinda an assassin ADC. How squishy was your team? If you had no tanks at all, I can see how you would be angry. I had a game just a few weeks ago where I, as Twitch, walked straight up to 2 assassins in stealth, popped out at max range, instantly 1-shot them and got a pentakill from that fight. However, afterwards they both bought Black Cleaver and all of a sudden I could do no damage to their Nocturne and Zed while they jumped on me and made me useless every fight by killing me 0.0000000001 seconds into it. That's just the way things go.

in this meta where things are so fast paced, hitting 2.5 items is considered late game.

In games that end at 20 mins, 3 items is lategame