Why would trust them? honest question. VSCode is more transparent as any other open source project it can be, yet people still have that Microsoft stigma for years ago. To me is just blatant paranoia.

I would not trust an installer from a third party without knowing what was really changed, that's scary as hell if you ask me. Just look at the bootstrap 4 backdoor that was introduced but luckily was caught.

Ah, that's because you are on an untrusted platform in the first place. There is no "installer" on ubuntu, so it's actually easy to verify if the package we got really came from the sources we see in github. But vscode packages are explicitly different from the code by those proprietary additions during build. We have to trust them that they only add telemetry. One very important feature of open-source is that you don't have to trust. Adding this proprietary blackbox completely removes that factor. Not to mention, I really don't want telemetry on my code and this wouldn't be the first time Microsoft let you disable something only to be later revealed that it was still sending.