malaysiakini and the BLATANT Double Standards of the POLICE

It was reported in the mainstream media how about 5000 Malaysians were allowed to stage a fiery protest near the US Embassy in KL; burning the USA and Israeli flags.
Such protests usually take place after Friday prayers so the majority of such demonstrators are Muslims.
It seems that the authorities allow such protests to occur as the police cannot/will not act against such a mob.
Contrast this against the action taken against a group of candle-light protesters -they numbered only 200 odd peaceful Malaysians and yet the police decided to arrest 21 of them even though the malaysiakini video shows no violent acts like burning effigies etc.
How are earth are the police ever going to win back the confidence of the ordinary citizens?
There is a definite lack of any principles applied to the police actions or in the case of the larger mob a definite climb down.