There is a quote commonly mis-attributed to August Bebel and indeed to Marx: "Antisemitismus ist der Sozialismus des dummen Kerls." ("Antisemitism is the socialism of the stupid guy", or perhaps colloquially, "Antisemitism is a dumb-ass version of socialism") That is to say, politically naïve people were attracted to antisemitism because it offered them someone to blame for the problems they faced under capitalism, which — to the quoted speaker's view, anyway — would be better remedied by changing the political-economic structure.

Jay Smooth recently put out a video, "Moving the Race Conversation Forward", discussing recent research to the effect that mainstream-media discussions of racial issues tend to get bogged down in talking about whether an individual did or said something racist, as opposed to whether institutions and social structures produce racially biased outcomes.

There are probably other sources for similar ideas from around the political spectra. (I'll cheerfully admit that the above two sources are rather lefter than I am, and I just couldn't be arsed to find two rightish ones to fit the politesse of balance.) People do often look for individuals or out-groups to blame for problems caused by economic conditions, social structures, institutions, and so on. The individuals blamed may have precious little to do with the actual problems.

That said, if someone's looking to place blame for a problem, that does suggest the problem is real. It's not that they're inventing the problem in order to have something to pin on an out-group. (It also doesn't mean that a particular structural claim, Marxist or whatever, is correct on what that problem really is — just that the problem is not itself confabulated.)