when it's acceptable and somewhat popular to say the same thing about whites, men, straight people, etc.
You're ignoring the power dynamics. Take trans women for example. 46% will commit suicide, over 80% have experienced assault (and only a slightly lower statistic for sexual assault). Thus a cis person saying something of the sort like "trans women should be murdered" is propagating an idea that has very real effect on the world. Since it is already accepted that trans women are harmed as such, making such a statement propagates the harmful ideas further. It is very likely that after that person makes such a comment, a trans woman will die.
In contrast, cis white men are not being murdered by trans women. Thus for them to state that "cis should die" is a act of protest, and has very little effect on the real world. The difference is: Is this likely to happen, is this happening, and has this happened? In the former instance the case is yes, in the latter the case is no.
Violence towards people labelled as fascists is common, but not the other way around.
On the contrary, fascists have murdered in recent years:
1 British politican (Joe Cox). 2 American Representatives. A number of American people[0][1]. I can bring up more examples but I'd like to get off this site sometime today :) Besides, it's trivial to google.
Indeed, White Supremacy is listed as one of the things that the US DHS is working to combat[2]
"death to cops" has absolutely led to an increase in people murdering police officers.
Source please? All I've seen is more police killing unarmed and already restrained people.
[0]: James Fields was a fascist. https://www.theguardian.com/us-news/2017/aug/13/charlottesvi...
[1]: https://www.theguardian.com/us-news/2017/may/27/portland-dou...
[2]: https://www.dhs.gov/blog/2017/08/16/did-you-know-four-ways-d...