Code changes generally require 3 things:
1. LGTM (that is, any second set of eyes)
2. Readability Approval
3. Owners approval (similar to github ownership)
The CL author can provide readability and ownership, if I have python readability and own the file I'm changing, anyone else can LGTM. But if not, at least one of my reviewers needs to provide the language approvals.
There's a process for gaining readability in a particular language, where you send your normal code changes to be additionally reviewed by experts who give deeper feedback on language idioms/use. This process is contentious because Google is fairly strict about style guides, and the readability reviewers goal is to ensure that you are writing idiomatic code, not to ensure your changes get submitted fast, so they'll often request changes and delay things (but this is known in advance, and for a high priority change, there are other avenues to get language approvals).
After you are granted readability, you no longer need approval from someone else with readability for changes in that language.
Personally, I found the process valuable for all of the languages I've gone through it in, but I can absolutely understand people's frustration, especially when dealing with deadlines or similar.