I agree with your point on finding the answers to every "why".
I recall during my first job, while building a contact form for a client, I made the form submit user-input via AJAX, and display a 'thank you' message in real-time.
My 'senior' dev told me to make the form a 'hard form' which loads a new page on submission. It took way longer to do that than than the original implementation, and he didn't seem to care.
I asked why, and his response? "Because that's how we've always done things". 🙄
His credibility as a dev was shot long before this for similar stuff, but man, I do not miss working for that company.
I wouldn't be surprised if there was a little fear of the unknown happening there. If you stop learning it becomes tempting to shut out anything unknown, for fear of being shown to be obsolete.
Heh, I've been that Sr. — doing the "...because that's how we do things..." or the ever popular "...because I said so..."
When I really meant "...because there are conceptual flaws in your approach that don't work for our audience and/or client and I really want to explain but I'm already 2-weeks late on my own deliverables and don't have time to explain why your solution isn't optimal. So save your solution, but do it this way and we'll discuss it when this project's out the door."
Hopefully I (and your former senior) get better at communicating the latter. ;-)
I say that tongue-in-cheek — my experience likely has nothing in common with yours. I understand the frustration, though. I've been both the Jr. Dev and the Sr. Dev in that scenario. It's always hard trying to balance mentoring with just getting stuff done. The same as it's hard to be new, intelligent, highly talented and both eager and hungry to do awesome stuff.
We're a place where coders share, stay up-to-date and grow their careers.
We strive for transparency and don't collect excess data.