Firstly, I never said that Bangladesh is a threat to us. Secondly, the issue you mentioned about North East insurgency is correct. But look at the context, things changed only when your government changed. Under Khaleda Zia those same groups found shelter in Bangladesh.
About tariff barriers, yes, Indian government could concede that to BD. But again, what do we get in return? Because BD will be the net beneficiary of removing tariffs. While that is not a problem, but surely, you do realize that asking that our next door neighbor does not have defence deals with a country that is a threat to us is not expecting too much?
I don't think anyone should have a problem conceding these things to BD, international relations are about give-and-take. But what will you give in return, if you cannot give the only thing that works for India?
IMO, this is the operative part. Sheikh Hasina is probably the best friend India has had as far as a foreign head of state is concerned. But Bangladeshi goodwill should not be contingent on her. The BD-China defence agreement was signed when Khaleda Zia was PM. She is no friend to India. What is the point of making concessions if there is no guarantee of consistency in relations?
See, even here, you are not agreeing to reciprocate despite what we have done for you. What have we got from India after solving the Northeast insurgencies and providing transit facilities?
Defence deals are separate things. We buy defence equipment from China because they provide them at cheaper price without compromising the quality. As a sovereign country, this is our own issue and India has no right to tell us what should we do. In that case, we can also ask why India is building the Sagar island naval base? Why such large Indian naval assets in Bay of Bengal?
In fact, the moment we bought submarines, India supplied ASW torpedoes to Myanmar. So India obviously is trying to send a message. We can't sit idle in that case.