According to the wiki, Interlink has been deemed to be potentially beneficial to Nepal and Bangladesh assuming proper water management treaties are negotiated with those countries.

Please point me to these properly negotiated agreements.

And pointing to the existing water sharing agreement with Bangladesh is dishonest. Putting aside the fact that it only lasts for 30 years and makes no mention of Interlink, everyone agrees that the treaty is inadequate, as evidenced by the massive tracts of arable land in northern Bangladesh that have fallen out of cultivation over the last 40 years due excess salinity caused by poor flow out of the Farakka Barrage.

So yeah: dick move.