I had argued for a less pedantic take, but I guess by replying to you I'm being pedantic. It seems to me that my example not only is bikeshedding by the definitions I find but also that to me it fits your definition of it. It's easier to talk about what framework you think is best than it is to talk meaningfully about process, which is more relevant place to look to prevent serious bugs, assuming both frameworks are capable. https://en.wiktionary.org/wiki/bikeshedding
Bikeshedding is when people need to make a decision on something, and keep talking and talking about the easy stuff. Your example of someone offering a driveby opinion isn't an instance of a group of people needing to make a decision.
Ah, it wasn't a driveby opinion how I imagined it, and I've experienced stuff like it in the past. It would then go into talking about rails features and libraries that could save the day, and the django counterparts. The decision that needed to be made would be what action to take to prevent a similar issue from occurring in the future.
I'm not saying it doesn't happen, but bikeshedding is when you say "OK guys we need to figure out the architecture of this complicated new service" and then there's a bunch of debate on libraries and frameworks and very little debate on the actual (hard) problem it needs to solve.
