ok let's be fair
even if your team wasn't feeding, your team would have lost because of malph adc aroung 80% of the time
you remove one of the most important jobs for teamfighting (Sustained adc damage) for a teamfight champion (Malphite)... but if you have no adc, why would you even want to teamfight?
Now I could understand if you wanted to go some troll shit like... lulu adc... because it kind of works
hell crittlesticks can get the job done due to his E base damage in lane as he builds his BIG RED NUMBERS
but malphite?
The fuck?
Dude i'm a massive troll, I'm m7 lethality garen mid only, I'm m6 crittlesticks only, my main is TANK JAYCE, my buddy and I both have alts specifically to only go urgot+Rumble bot lane
you can't troll pick bot lane unless the hole you make in your team comp is filled by you or someone else (Rumble+urgot goes with a kindred/graves jg, or quinn top or lucian mid etc, Crittlesticks works because he's got ranged AA's and still does good CC to help him self peel or duel easily)
I thought your post was gonna be about people who complain about non-optimal, but if you're gonna go some weird ADC shit at least make sure it does the job of the adc, go like.. idunno, master yi or yasuo or something if you're confident? Or make sure it perfectly compliments at least two of your team mates, so malphite adc if you have like an ornn top and a yasuo mid? you'd still need a lot more damage though so yeah even that, you'd need like... brand support and something I can't think of right now for jungle (Graves or an AOE spash monster jungler?)