True, but consider the following:

1) The people themselves don't know how easily they are manipulated.

2) Facebook analyses this about them, and helps other businesses to use this against them.

3) They do not know Facebook helps other businesses to use this against them.

That's problematic. At the very least, #3 should be solved ie. they should be informed beforehand because then at the very least they're informed about the malpractices. You can then make a case about it being allowed, or not. But you cannot make any informed case if you don't even know it is occurring.

Are you going to defend this as being good & moral? Because the claim was simply that this doesn't seem to fit under good & moral.

You have positive, neutral, and negative. This doesn't fall under positive or neutral.