- Swiss German and Austrian German didn't make the cut because Switzerland and Austria are on good terms with Germany and don't mind if we call their languages a dialect of German. Not only is that justification to exclude them, they are also not in Google translate for this reason (which this map uses)
- Luxembourg did mind and went to great lengths to get their German dialect recognized as a separate language, is in Google translate, but Wikipedia lists them as only 300k speakers
- Frisian is seen as a distinct language because of how different it is, is in Google translate, but has about 200k speakers
- Similarly, Scottish Garlic is in Google translate has only 70k-200k speakers
The map is consistent if you set the goal of only considering languages that are in Google translate and have at least 500k speakers.
I do think these rules detract from the map. Frisian and Luxembourgish are interesting as "in-between" languages (Luxemburgish has a lot of French influence, Frisian is closer related to English). And Swiss German has many distinct words that are very different from their German counterparts, so for the purposes of this map it really should be a language.