Whilst I agree that Bash makes it far too easy to do it wrong, it's not too tricky to write scripts that don't have those issues.

Possibly the most important tip is to use ShellCheck (https://www.shellcheck.net/) as a linter on your scripts and work through the various warnings to eliminate them. For the rare times that ShellCheck is overly cautious, you can remove a specific warning with a comment before the offending line such as

  # shellcheck disable=SC1091

Also, take time to look through Greg's Wiki as it is possibly the best Bash resource that discusses the various pitfalls: https://mywiki.wooledge.org/BashPitfalls

As a Bash script writer, I disagree with your "red flag" interpretation as that'll mean that you'll end up with poorly written Bash scripts along with a hotch-potch of different tools to achieve the functionality (e.g. different versions of Python required for older scripts and newer ones). Knowing Bash is also very useful for writing Dockerfiles.