I agree with everything in your post.An American president can tell India or any other country "don't do this", or "we'd like you to do that" - but they don't have to obey. And in many cases they don't, so to not look like a puppet to their own people. How many times over our history have U.S. presidents given "political cover" to foreign leaders, making those leaders look independent of U.S. pressure, possibly applied from behind the scenes?? Diplomacy is about many things, and putting a pleasing face on an issue involving several countries is a delicate balancing act for any president.
I have no idea of what goes on behind the scenes in any administration, concerning deals / pressures / threats / agreements, etc. I'm sure for national security reasons, and political ones - either U.S. politics reasons, or global politics reasons - we aren't let in on every little thing. It's that way in every administration, R & D both. Sometimes it's best not to blab every detail out to the whole world. I lose no sleep over that sort of thing.
The world oil markets are always in flux / turmoil, because the leaders of a number of countries have huge ego's and they realize they have leverage in world markets. According to numerous economic and investment sources (one of which is Forbes), the U.S. is producing more oil & gas than it ever has - ever. Oil producers aren't going to stockpile and save it all for U.S. consumption ........ they want to sell it and make profit today - not in 6 months, 1 year, 5 years. Despite the fact that we produce more oil & natural gas than ever before, we sell our resources on the world market and still import oil. Doesn't make sense, does it? I won't try to figure out how & why world oil markets act as they do. Things that would seem - to me - to make sense from our U.S viewpoint ........ don't happen. So I agree with your last sentences above. Nothing is as simple as we'd like it to be.
I do believe the Indian government is possibly violating sanctions against Russia though. The U.S. could apply pressure on them to knock that off.