I think its because he could and should have got us to the top. Just his cautious,negative streak , coldness and ego instead turned us into a mess. a mess that we are still trying to get out of today.plus he wasted a lot of cash,did zonal marking, rotation policy etc. lots of reasons he isn't wanted back, the most important being the sense of deadness in his last seasons.
Now I know for certain that you know nothing. You don't suppose that LFC being one of the toughest teams to break down in the league and had the most clean sheets for 3 consecutive seasons had anything whatsoever to do with zonal marking? Put down the newspaper and open your eyes. We conceded goals using zonal marking - other clubs conceded goals using other forms of marking. I would never have expected that! Let me save you some trouble and spell it out, even though you hate stats because they disprove your argument.
04/05 - W17 D7 L14 GF52 GA41 GD11 Points 58, 5th in league, CL title, league cup SF (5th fewest goals against in league)
05/06 - W25 D7 L6 GF57 GA25 GD32 Points 82, 3rd in league, FA Cup, UEFA Super Cup (2nd fewest goals against in league)
06/07 - W19 D11 L8 GF57 GA27 GD30 Points 68, 3rd in league
(2nd fewest goals against in league)
07/08 - W21 D13 L4 GF67 GA28 GD39 Points 76, 4th in league
(3rd fewest goals against in league)
08/09 - W25 D11 L2 GF77 GA27 GD50 Points 86, 2nd in league
(3rd fewest goals against in league, most goals for in league, best goal difference)
09/10 - W18 D9 L11 GF61 GA35 GD26 Points 63, 7th in league (3rd fewest goals against in league)
Consistently 2nd or 3rd best defensive record in the league over his final 5 seasons, including the dreaded final season. Yeah, zonal marking sure did suck.
And is it really to hard to wonder whether the sense of deadness in the last two seasons had nothing to do with the owners saddling us with 45m pounds of debt each season and taking money from player sales out of the transfer budget? No! Of course everything was Rafa's fault, from the bad results to the bad tea.