Well, Wikipedia's got two sentences and one citation on it, so it's really specious in itself, but that's beyond the point- the Landtag was a bicameral parliament with a House of Lords, so it follows that Communists would support abolishing it on the basis of instituting a legislative body that would reduce the influence of Germany's ruling class rather than any actual coordination with Nazis. It's also extremely unclear whether or not it was the official position of both the Nazis and the KPD, or if it was a measure supported by it's rank-and-file members individually. It's basically "How dare you, Hitler also promoted vegetarianism and non-smoking, so your opposition to my BBQ /Cigar Treat Ritual is Nazism, actually" writ large.