No. There are numerous self-identified Marxist historians, and Marxist history is taught and published at a high academic level.

Source: http://www.historicalmaterialism.org/journal, a peer reviewed Marxist journal often included in non-Marxist compilations.

Not in my experience. The Marxist social theory which is foundational to social science as we know it and Marxist political theory are not strictly the same thing. There is a difference between a methodological framework and an ideological framework though the two naturally can and do coexist quite often in the same work.

Simply put, I don't have to believe in the eventual decline and fall of the bourgeoisie but I can still use Marxist theories of power or socio-economic order to inform my interpretation of historical evidence.

Now, this is all debated, and you do get challenges about the use of historiography and social theory but this isn't strictly limited to Marxist historians but can be seen as a historiographical fight between lumpers and splitters over the use of evidence. If you do see Marxist historian being used as an insult the case may be that the accuser believes (rightly or wrongly) that the accused is (a) over-generalising historical data or (b) abusing historical data to serve a primarily political point.

And as /u/daedalus_x has noted, Marxist history is a broadly accepted church of history bound by methodology if not necessarily ideology.

I think it might depend on the biases of the person you're talking to - I definitely had a low opinion of Marxist approaches as an undergraduate, and there was a lot of Marx-bashing (and Marxist historian bashing) in one of my graduate historiography seminars. I think this comes as a reaction to the stereotyped materialist Marxist approach that tries to boil everything down to economics, to the point that the people and ideas are lost behind discussions of 'class struggle.' I do confess to muttering 'such a boring Marxist!' at a few authors who insist that trade and taxes are the only thing worth talking about in every. single. thing. they. publish. But while this kind of (boring) Marxist history does exist, there's also a lot of very exciting work being done that wouldn't be possible without Marx's influence.

Most of the approaches I value as a historian trace themselves back to Marx. The ideas that ideologies and values systems are tied to social conditions, that human actions and social rules are mutually structuring, and that historians can't ignore the present political implications of the scholarship we produce are all ideas that trace themselves, in important ways, back to Marx. All my favorite books use some form of approach developed out of Marx's ideas.

So while I think some people do look down on a simplistic, stereotyped version of Marxist historiography, history as a modern discipline would not be where it is without Marx's contributions to western thought. And most historians, I think, recognize this.

Aside: what does Marxist historian mean? A historian who studies Marxism? Or a historian who studies various chapters of history through a Marxist lens?