I think this is an example of athiesm being used to justify imperialism in much the same way that Christianity used to
"those people are savages who worship false gods and need to accept Christ"
"those people are savages who worship false gods and need to accept secular humanism"
the poster seems to be an Indian nationalist of some sort
To call this a "trend" is a bit odd given that this has happened ever since religion was created. Not that it's happening because of religion, it's just another label used to segregate people into in-groups and out-groups, a justification for why some people should be treated as lesser than others.
This is just basic-ass bigotry, not even with a new paint job. If it wasn't religion, it'd be ethnicity or sexuality or origin country, whatever. Any arbitrary classification can be used if you're a right-winger trying to enforce your fictional hierarchies.
What's kinda funny about this person is that they seem to think that them being "ex-muslim" somehow releases them of the implicit islamic skull shape that predisposes them to cause problems or whatever.
I think it's a new trend in athiesm as previously athiesm wasn't an accepted part of the established order but I think people like Christopher Hitchens made a devils bargain so to speak to in exchange for political legitimacy play the same role in justifying colonialist violence as Christianity used to
I have known athiests who speak about Muslims (it is almost always Muslims as they are the enemy de jour) using language and points I recognise from 18th century colonial justifications