The company control their private property.
The labour can only control their own labour, so they choose to use that control.
How is that not in their right?
I totally agree, they all have the right to not work there, but they don't really have a right to prevent others from delivering packages to a building.
Yes, but people still have the right to say "Pay us $X and ensure safe working conditions or we strike" Tesla can either withdraw or negotiate. Nobody's right is infringed here, it's just free market. Especially as usually the workers have it worse than companies.