Let's see if I can shed some light:
1. When you delete an email message you do confirm you want to delete and even then the email is held in a trash bin for complete deletion, again making sure you fully wanted to delete said email message. When you delete a text message, it's gone, unless you have a backup with the message and even then requires you to restore your phone from the that backup, deleting anything else you've put on your phone since that backup was made.
2. Notes are also stored in the cloud (you can confirm by going to www.icloud.com) but messages are not, so again, one has a way of getting a note back, but not a text message.
As to your suggestion to have a toggle option, I would have no issue with that. But you're arguing with users on a user to user ONLY forum. You're not speaking with Apple and Apple isn't paying diddly squat to your post here.
Arguing here is a point in futility. You are as welcome to let Apple know you don't like this as I was to thank them (yes I did thank them) for adding this by providing input via this link: Feedback - iPhone - Apple