hans, I'd argue what is displayed here is not cavalier (ehm) attitudes but the word of applicable law. At least that's what I tried to relay in my post, happy to underline the intention now. And that law does not preclude you from returning back. Au contraire it forces you to apply judgement and exercise authority when taking the decision whether to fly or taxy back.
Moreover, the principle of dispatch moment being the start of taxi under own power is also known to the people who write and certify the MMEL.
Your second point is an excellent illustration to the different protocols (with missing links that I allude to above): Imagine that in pinteam's situation: his entry in the logbook must be counter-signed by approved line-maintenance. So, unlike you, he has the need to continue without recording it pre-takeoff, and the law entitles him to do so. Different strokes for different players.
Writing the above I already got two ideas (case studies) where - based on your wisdomly posting history - I'd bet half a bitcoin you personally (in the door warning situation) would just set the burners full and be gone to worry about the paperwork later.
But there's a better story, not a week old. Upon receiving the taxi instruction, I flicked the taxi LT switch and nothing happed. That's pre-dispatch.
- hhhmmm ....?