In which case your question is the same as to why we have decided it is not acceptable to restrict individuals. The question is then to ask why is it acceptable to restrict the government but not individuals? Well, lets see. Because the government is made up of the people. The people being you, me and every citizen in the country. You, in your home, have the liberty to choose to restrict yourself with regards to your own property or not. The people who own the corporation, which likely includes you if you own any stock, have decided to place no restrictions upon the company you own. The simple reason is, because we have decided to place some restrictions upon ourselves, but not others.
If you want to know why that is, I suspect we all have our own reasons for this. But let me ask you this, since you believe businesses should be restricted. Do you believe you should be restricted in the same reason as the government? Do you believe you getting together with a couple of people for some reason means you should be restricted in the same reason as the government? Do you believe you opening a store means you should be restricted in the same reason as the government? Do you believe you opening a store with a couple people means you should be restricted in the same reason as the government?
A business has no rights that its owner(s) do not. To remove rights from a business is to remove those same rights from the owner(s). So just because someone decides to open a business, alone or with other people, is no reason to deny them rights that those who do not open a business have.