If it's your property, how are they forcing you to do something you don't want to do? Is there some extenuating legal circumstance?

No. There is nothing like that. My land developer said that we need to do as they say as they are very popular and the backyard neighbor is also a politician.

Politician or not I would tell him to shove it where the sundoesn't shine. Plant what you want. If he wants privacy then it up to him to plant it in his yard. He can't do anything to you as long as you don't do anything illegal. Just as pleasant as you can tell him what you are planting, that YOU want and walk away. Not that it is none of his business.

If you let him bully you this time, he will keep on bullying you as long as you live there because he knows he can get away with it. Nip it in the bud, now.

Hmm. While being on the good side of those in power is often a nice thing and can come in handy, teaching those in power at the outset that you'll cowtow is rarely a good thing. Which master do you want in your lives? Tell us if you want to be at their mercy long-term or not and we can better address your dilemma.

Having said that, there are potentially ways around an obvious snub to them. As mentioned, you can nicely tell them they are welcome to plant whatever they wish on their side (or, if you don't object, on yours, although that may open its own can of worms), communicating that you know they'll do a fine job given their existing landscaping (whatever its current state). Or a sincere apology with a polite, "We appreciate your input and concerns and we'll do our best," and then do whatever or not suits you and hope to move on.

I have decided to plant Container Privacy trees; that way neighbors have their privacy and I can plant the trees I want.