Observation: As Paul begins his letter to the Romans, he has his section where he discusses the fact that the majority of people act in a manner opposed to the Lord's will and precepts with all manner of unnatural sin. He introduces this by stating that, because these people should know God by the very presence of the created world all around them, that the Lord is therefore justified to judge them and bring wrath down upon their wickedness.
What is interesting is both the justification (that all nations have been shown who the Lord is through the nature of the created world itself, and therefore have had the chance to learn about the Lord and know better than to sin) and the wrath. We have contextual history of this age and might guess that "wrath" looks like ... nations being destroyed by Rome, Rome being corrupt and violent, and in general life being difficult and relatively short for just about everyone. However, Paul talks about another type of wrath.
The Lord ... allows them to sin.
Paul says that, instead of helping these people have better lives, the Lord "gave them over in the sinful desires". In verses 24-27 Paul says this wrath includes allowing unnatural sex (very, very clearly what we would call LGBTQ+ today), and then include other items he calls a depravity of mind, such as greed, envy, strife, deceit, malice, and gossip.
In other words, here is what the Lord's wrath for those who have rejected him involves. He allows them to pursue a life that involves depraved relationships with others. He allows them to pursue thoughts that cause them stress and anger. With these two elements alone, consuming all their heart's and mind's attention, their lives devolve into shambles. And the Lord just allows it.
Application: One of the things I often think of with people today - with great sadness in my heart - is that the "causes" they fight for are beyond just sinful and evil and bad for them. They also become an all-consuming and central component of their core meaning in life. For those who pursue these causes - which might be one of the social issues I hate but can also be their high-paying job, or membership in their country club, or even hatred of the social issues or corporate big-wigs or country clubs - the cause is all they think of, and it does not bring them happiness. Quite the opposite, spending their day plotting in bitterness ... or planning for conflict ... or brooding over perceived hatred ... or sitting alone in anxious isolation ... all these conditions create such an empty life.
Now I see the "why" for God allowing it. God doesn't put an end to these issues and causes in order to protect the world from them. God allows people to live into these causes as the wrath he brings upon them for rejecting Jesus.
That also means that delivery out from those causes is a mercy available from the Lord, and he grants that mercy every day when people turn to Jesus. These causes work within the Lord's plans and purposes, as they show what an empty life looks like, contextualized against a life of joy and wonder when one sees the Lord in nature, in others, and in the sacrifice of his son.
Prayer: Lord, I admit that the list of sins that bring wrath upon others includes acts I am prone to commit. Again today I say, please forgive me for my sins. May my heart continue to reject all those things, so I may fully enjoy the world and the life you have blessed us with. Amen.