The reason is not very difficult to decipher.
Mulayam knows that in the coming Lok Sabha elections he will face stiff anti-incumbency challenge from both Congress and BSP for Muslim votes.
In state elections, SP still remains the first priority for Muslims , but in Lok Sabha elections the equation can change dramatically because this time its Modi who is seen as knocking at the doors of 7, Race Course Road and at the national level it's Congress, and not SP, that can put the brakes on the BJP juggernaut .
Mulayam Singh knows it very well and that's why political observers are of the opinion that Mulayam should have been the happiest person had this yatra taken place.
This yatra would have given Mulayam Singh an opportunity to tell Muslims that the dangers of BJP and communal riots are still looming large over their heads and that it's the SP only which can take a tough stand against Sangh parivar outfits the way it did in 1990s.