Sure, modernism could include German Expressionism, but I had in mind Art Deco, Bauhaus and Modernist architecture, along with visual art movements like Dada, De Stiji, Cubism, etc. - the things that are typically referred to by the word modernist. The qualities these things have in common tend to be distinctly different from the qualities that the Gothic has usually had.
According to historian Roger Griffin, modernism can be defined as a broad cultural, social, or political initiative sustained by the ethos of "the temporality of the new". Griffin believed that modernism aspired to restore a "sense of sublime order and purpose to the contemporary world, thereby counteracting the (perceived) erosion of an overarching 'nomos', or 'sacred canopy', under the fragmenting and secularizing impact of modernity".
https://en.wikipedia.org/wiki/Modernism
This focus on the new and future is definitely not something Gothic does, which is traditionally very focused on the past.
In architecture, for example, the Gothic lost most of its influence:
New architectural movements, sometimes related, as in the Arts and Crafts movement, and sometimes in outright opposition, such as Modernism, gained ground, and by the 1930s the architecture of the Victorian era was generally condemned or ignored.
https://en.wikipedia.org/wiki/Gothic_Revival_architecture
And again, the purpose of the article was to trace the term gothic through history, not to explain the influence of the Gothic in toto. These films may have been influential, but they were based on already written Gothic works, and they weren't dominant in the way Gothic architecture or literature were in the Victorian era. Gothic in the 20th century was more of an influence on other art movements (including German Expressionism), not a fully-fledged art movement itself, as it had been in the past.
Overall I agree that a line about the films would have been good to add, but I don't think it was necessarily essential to tracing the word gothic through time. The term was applied to music because of the location "in the gloomy vaulted wine cellar of the Delmonico hotel, not because of a reference to the films.
https://en.wikipedia.org/wiki/Gothic_rock#Characteristics
I'm not sure why this single point "doesn’t really connect the dots" for you, considering that the rest of the post covers dozens of other significant influences over two millenia.