Assuming that God is real, and created everything including humans with a long-term purpose, it would be sensible for God to be "jealous", I think. It would be like a human father being upset if his children disowned him and went around saying a wooden statue in their backyard was their father.

Those verses also say that God shows mercy to thousands, or alternatively "to the thousandth generation", which means says God is much more merciful than punishing. The "iniquity visited on the children to the 4th generation" is presuming that the children are continuing in the sins of their ancestors. Genesis 15:16 talks about God intending to punish the Amorites for their sins, but seeing that it was a collective national judgement, holding off for a few more generations until such a time as their national sins really justified it. Genesis 18:16-33 also talks about Abraham asking God about His character—would God destroy Sodom and Gomorrah if there were as few as 50 righteous people in it? In the end God said, no, if their were 10 righteous people in a city, He would spare it. Sounds pretty reasonable.

It doesn't need selective reasoning, just taking the scriptures at face value.