The main reason for his record being a joke is that unlike Warne who constantly faced the worlds best batsmen all of his career, Murali copped alot of cheap wickets against the likes of Bangladesh and Zimbabwe.
If Warne had been bowling to such average opposition as often as Murali he'd have taken 1000 wickets.
Look at Murali's milestone wickets
150 vs Zimbabwe
350 vs Bangladesh
400 vs Zimbabwe
550 vs Bangaldesh
600 vs Bangladesh
700 vs Bangladesh
And besides his 200th wicket at the Oval the rest of his milestones were almost entirely on average subcontinent pitches.
To be the best you need to constantly play against the best, Murali never did that.
Murali played 27 test for 163 wickets from Bangaldesh/Zimbabwe contests.
Warne I think played 1 test vs Zimbawe and 1-2 vs Bangladesh.
Murali's record is a farce.
Why are you so desperate to deny the man his record? Do the other 550 test wickets (still more than most bowlers manage in a career) he has taken not count in your mind? If you want to argue that wickets against weak sides should be discounted then maybe you should knock 155 off Warne's tally that he took against poor England sides over the last fifteen years.