Yes, I agree. I'm arguing against your characterization of node as a poor runtime. For many line-of-business applications node is a fine choice. However, plaid has to integrate with many banks which only expose web pages, not APIs, so I'm guessing that they have to do a non-trivial amount of CPU work to scrape and process HTML responses. For this, it may not be such a good choice.
All I'm saying is that the choice of language is (usually) not the issue. Poor architecture design causes a lot more problems than whether you choose python/java/ruby/node for your webapp.