In the first screen you are trying to trade a bunch of Missile Defense Techs. The problem is that the only one that the AI cares about is the highest tech. All the other lower techs are meaningless and have no value to the AI. Who would want PD COmbo I, II and III if you're also offering Aereon Missile Defense.

To get value out of a trade like this you need to trade PD Combo along with some totally different tech to get what you want then you can later trade PD Combe II for something else later on. But once you offer them a higher tech in the same path you get no value for any lower techs in the same branch.

Note you can use this fact to your advantage. Get an AI to trade the top line of most anything (note cumulative total techs like logistics and miniaturization are ecempt from this) and once the deal is set you can include all lower tecs for free.

In the second screen the problem is that you probably have a stronger military that they do so they won't trade "weapons techs". Advanced troop mod is considered a weapons tech.

Note that your diplomatic advantage doesn't help in either of these situations.

It's just hard-coded in there to decline any trade if the pre-req for it is also on the table.

Ideally though, I think it should still allow the trade to go through, but the obsolete techs should be worth a percentage of their original worth.

Another thing to think about when trading techs to an AI. When you have multiple techs on the table, their individual cost goes down. Buying in bulk. So if you are trading techs to a race for cash, do it 1 tech at a time.