There is no vague meaning. Perceive means detect. Blindsight does not say "detect location", but perceive surroundings as in everything. Stealth doesn't work against them within the range. It's not a vague rule. Not sure why anyone is trying to make it one. There is no Blindsense and Blindsight now.
You can stealth on someone with truesight. But not Blindsight. Nowhere does it say perceives with hearing. So moving silently is irrelevant.
At this point in time barring any clarification from the developers, if you are within a dragons Blindsight range it knows you're there whether Stealthing, invisible, or what not. It's not even something open for discussion unless you're somehow arguing the meaning of the word perceive.
I don't think I agree with this. There is nothing in Blindsight that negates stealth entirely. Blindsight not only gives a description of what it does (perceive surroundings without relying on vision) but it also gives examples. Grimlocks have blindsight because of their heightened hearing and smell. Gray oozes have some sort of magical sense. Bats have echolocation. Dragons have heightened senses. While using stealth would be tricky, it should not really be more difficult than if the creature could see you visiually. Releasing sources of strong smell and loud noises would allow stealth out in the open past grimlocks, and being behind cover should allow stealth past bats, dragons and oozes. So there should be means of still using stealth even if it is more tricky.