Why isn't "allow-parallel-runners" used by default?

[leonklingele]

I was wondering and couldn't find a reason why the golangci-lint config option allow-parallel-runners is not enabled by default. Is there any downside to not allow concurrent executions?

The locking mechanism to enforce sequential runs was introduced in #812 while opting in to parallel runs was added in #1070, both changes unfortunately without an explanation on why they were made.