UPDATE: I asked the local lawn mower shop about cutting that piece off. he said it was a brace for the deck and if you cut that piece off it will crack the rest of your deck. sure enough my deck had 5 or so cracks all over it (my plastic deck brace was cracked before I removed it). with the plastic piece cut off I can bend that part of the deck with my hands (it does springs back). I bumped down on the sidewalk and the front flexed down and the blade cut a little but of the front center of the deck.
I had to bust out the welder with this one. welded up all the cracks and made a brace that goes over the top of the deck so it does not block the grass flow. the brace looks a little ghetto and id do it slightly different next time, but it stiffened the deck up nicely. i have not been able to clog it, almost never "mohawks" the grass. i don't even have to raise the deck to mow tall grass. its a beast
i would only cut of this piece if you can weld up a brace and want to chance the deck cracking. but hell there cheap enough you could just throw it in the gutter and go buy another if it messed up the deck.
and yeah i have the mulch blade removed.