Have people noticed how much popretary java code ProtonMail requires when using a web browser for email?
You mean JavaScript; particularly, https://github.com/ProtonMail/WebClients.
Also, why the required login on their free VPN service if they are all about privacy and encryption?
Because they need to limit how many instances of the VPN you're concurrently accessing somehow.
Why do they want someone’s network traffic in order to use their free VPN?
To use a VPN, you by definition are giving someone your network traffic.
Over the past 6 months my suspicion grows bigger and bigger of who is behind Proton, the agenda behind starting the service, and how it caught on? Why don’t free encrypted anti-government services catch on?
I'm not even touching this...
Until ProtonVPN removes login requirement and release VPN server code under open source license like RiseupVPN or CalyxVPN
That would be meaningless. You login to a protonmail account, which you can create anonymously. The server code can also never be verified to be what's running on the servers.
I will choose to treat Proton like a spy agency.
Go for it.