Its a good point some people regard right wing as keeping to religious laws and ways. So where does someone like me sit on this. I am an Atheist but still believe in right wing policies. For example Capitalism is the best future for mankind, not Socialism or Communism. The UK where I come from does not get tied down with religious beliefs. In fact the UK has a quarter of its population claim to be Atheist/Agnostic or having no religious affiliation. Whereas say 20 years ago the fast majority would claim to be believers and mainly of Christian following. This trend is happening in most countries but particularly in Europe.

Probably more so an overall tradition of many things which includes religion.

The real cultural decay in our country is that created on the political right. It is a mixture of (1) a culture of corruption and greed which seeks to cheat, use, and abuse others for personal gain, (2) evangelicals in a blatant attempt to co-mingle politics and religion as a means of forcing their dogma on us all, and (3) the creation of a culture of white supremacist ethnocentirsm and racism to seek white dominance over all others.

It is this vile brew which has increased overt racism, which enabled the acceptance and support of Trump, corruption spreading in both business and political sectors, and growing incivility toward anyone who dares to challenge those malignant movements. And they have the gall to talk about cultural decline when they are the main force in such decline.

To many it means the lack of religious values. A now dead friend of mine said that by marrying a black woman I was "destroying my race." Is "white" that important to him? Put these two together with the Trump Fascists and you have what is going on today. Stephen Miller reportedly told a Latino friend of his that they could no longer be friends because he "was Latino." Fears of a power shift run deep.

The Nazis talked a lot about cultural decay. It meant Jews and communists back then. I'm sure Islamic regimes use it in relation to Western values too. I think it generally means you don't like where we're heading and want to retreat into a mythologised history.

I see two key drivers:

-A conservative mindset is uncomfortable with change of any kind. Political, racial, economic. This is well studied and applies throughout the world.

-Racism. Cultural decline is not-hidden code speak for more non-whites. It's fine to be "diverse" when nearly everyone is a white European. When the population mix changes as it is in the US, more Hispanics especially, the racism becomes much more virulent.

Yes

"Cultural decay", is likely the deviation the right perceives from the subject matter as portrayed in Norman Rockwell paintings.

This cultural decay thing has a long tradition in right wing politics. It goes from "back in the day art was better" to "the jews are ruining society by altering cultural norms". Think of it this way, for someone on the right wings all the necessary components of a good society are: everybody is one race (white) and everybody adheres christian norms (moral, gender roles etc.). In their (uneducated) notions of history back in the day this was the case.
Empirically all this is wrong of course but their biases only let them see the "negative" today and the "positive" in the past.

One of the low points of Romes decline was when it was put up to the highest bidder. You get that every election.

It's because society isn't catering exclusively to straight, white, Xtian males any more.