Twitter hides Donald Trump tweet for “glorifying violence”

No. No it isn't. That's patently ridiculous. Almost every decade of the past couple hundred years has consistently seen better human rights (in the Western World at least).

We're talking about: the elimination of slavery, establishment of women's rights, childrens' rights, elimination of colonialism, elimination of authoritarian rule by non-elected persons, elimination of torture, the right to freedom of speech, the right to a fair trial, single digit illiteracy, near zero deaths due to hunger, reduced systemic oppression against minority groups, reduced systemic oppression against non-traditional sexual orientations, universal access to free basic healthcare (caveat: every western country except the US), universal access to free basic education, and, in my lifetime alone we've added access to affordable and near-instant worldwide communication with the right to use it anyway we see fit (within reason). [0]

Now, how (besides the environment) have things gotten worse from a human dignity standpoint in the west?

The one example you gave was indeed a decent one. I know there are other good ones but there's absolutely no way they will add up enough to tip the scales so that you can argue human rights and dignity have gotten worse overall.

----- [0]: The list provided contains generalizations about "Western Countries". The list is incomplete/imperfect in that there will be some exceptions/caveats. In other words, yes I'm sure someone could find something there to nitpick but it's generally true in the big picture.

You use 'dignity' to mean, I think, that an individual has been granted autonomy. So a woman is now free to sleep around, terminate her pregnancies at will, and live her life however she pleases; she has rights. To you, she is being treated with dignity because she has autonomy. But that is not, I think, the way the 19th century mind thought (obviously this is a generalization; but think in terms of the kind of person who would have defined what 'common decency' meant in 19th century America). Dignity back then had to do with comportment and behaving well. What you call 'dignity' they would call 'licentiousness', and it would be considered the antithesis of dignity. One of the words for such a woman was 'indecent'.

You can argue that political correctness is just the decent way to speak, but to assume that it is 'common decency' is to assume an awful lot, especially when using that phrase to put down approximately half of the US electorate. The disagreement on just what constitutes 'common decency' is the exact issue here. One cannot resolve the issue by appealing to it. Conservatives and liberals have a different idea of what is offensive/harmful and what is decent because they have different fundamental values.

Or at least some of them do. A whole bunch of people on all sides are just engaging in thoughtless tribalism and mood affiliation. You are not one of the thoughtless ones, obviously. :)