who should prepare for IAT and NEST??

is it acttually necessary to qualify JEE mains so that we can think to prepare for IAT???.... i read some post and people be mocking those who scored 50s 60s percentile and thinking to do prep for IAT.... can anybody explain why is it so... can people scoring this cannot do anything in IAT in this 3 months of time??... what's the matter... and why people here be commenting only on rant vent post and not on actual helping post and instead do negative comments ??