There have been a lot of controversial cases with Italy involved tbf right from Quattrochi and Bofors, to Finamerica and now this.
Look, apart from how absurd it would be for a politician to favor his former country over his new adopted one (I'd be actually expecting the opposite, but whatever), I'd be surprised expecially for Sonia Gandhi to care this much about Italy given that we're one of the most individualistic people on earth (you'd have a hard time finding an italian proud of Italy and of it's achievements [apart from football]). In fact, we're probably world champions in loudly despising and hating our own country wherever we go (something that has also something to do with the massive exposure of this case over here) and I can't really say that her decision to leave does give her points for attachment to the motherland.
So yeah, BJP can maybe use this as an electoral gimmick, but it really, really looks just some demagogic babble or, at best, an overtly simplistic analysis.
Possibly, but BJP has already had a government from 1999 to 2004 which ran a full term under Atal Bihari Vajpayee. It was certainly better than the current UPA regime which has messed up economy due to faulty policies, and is mired in corruption scandals all over the place.
(a side note, I must say that Indian politics reminds me of italian politics in the '80s, with Congress in the role of the DC, 40 years in charge, nepotistic and corrupted but with some measure, and the BJP in the role of the new idealistic parties riding the wave of 'the old class is corrupted' and 'let's move this country forward'. I just hope it won't end like here, with people eventually complaining that 'it was better when it was worse')