Some professional experience might change your tune about the approachability of open source.
You'll likely be tasked at some point on a team building a large system that has components that are closed, components that your team is writing, and open source components. Inevitably some interaction between those spheres will lead to a failing test case (or bug report). You'll be able to see inside the open source (and ask informed meaningful questions about it on the Internet), see inside your team's work and discuss it with your team, and have to trust the documentation of the closed stuff.
Your definition of which sphere has a lack of approachability will change rapidly