^Because Cena has been the face of the company since last 8 years and still hasn't put over anyone clean.
Look at the Rock,when he was the face of the company between late 1999 to mid 2002,he put over Angle,Jericho and even passed the torch to the man of the new Ruthless Aggression Era i.e.,Brock Lesnar.He even tried to put over Hurricane by losing to him on Raw.
While Cena hasn't put anyone over yet.Look at Nexus,they were huge for some time but what happened, Cena single handed destroyed them and their credibility.Cena also buried Bobby Lashley.
he put over lesnar clean because he was on the way out and didn't think he was coming back at the time, when rock was on top he never lost clean, top guys in wwf have never lost clean (of if they have its extremely rare)
jericho pinned rock with feet on the rope at rumble 2002
jericho pinned rock at vengeance 2001 when vince interfered and jericho low-blowed rocky behind refs back
jericho pinned rock at no mercy 2001 when steph came into the ring and distracted rocky
not bothering to look back with angle because i know for a fact rocky never lost clean to hhh so he isn't losing clean to kurt, hurricane he lost when austins music distracted him, that match was nothing but a stopgap to build for austin/rock at mania 19, didn't cena get pinned twice on tv by justin gabriel ffs...
how exactly did cena bury bobby lashley, they had a 4 star extremely competitive match lashley came out looking a much bigger star after than match than billy gunn did after his match with the rock at summerslam 1999
you look back and i bet cenas lost as many clean as rock, austin, hogan, hhh did when they were on top, cena lost clean to randy orton at hiac 2009, he lost clean as a whistle to khali at snme back in 2007, lost clean to jbl at gab 2008, lost clean to hhh at noc 2008, lost clean to batista in their first ever match at summerslam 2008, he also failed to beat punk at mitb 2011, summerslam 2011, raw 1000, summerslam 2012, night of champions 2012....5 matches in a row he failed to beat punk, do you think rock, austin, hhh or hogan would have allowed themselves to not beat punk 5 times in a row