First, because if you are on a Linux distribution, you will tend to only take binaries from trusted sources like distribution repos that are imperfect but still audited and work on having reproducible builds.

Second because you can usually contained a closed source binary, let's say 'zoom' for example, but here the root goal is to open a pipe to the internet and give access to the console or local network, so it will be hard to check what it does and constrain it in normal operations.