Re: Why?!
Those rights are nice, but not fundamental. The analogous rights are rarely available. For example, if I buy a table, I am given a table. Nothing more. I have the right to use the table as I wish, and to disassemble, modify, or destroy my table. If I rented the table, I may not have all those rights. I don't have the universal right for the table manufacturer to give me their engineering plans for the table, although it might be useful if I was modifying the table. That is a thing I have to figure out on my own if the company doesn't want to get those for me.
The same is true of software. I have a problem with people who sell me a license to use their software in its shipped, compiled, form but implement that software in a way at odds with their license (for example, saying the license will work perpetually but requiring it to be renewed, or saying the license will function on airgapped machines but requiring an online check). I have a problem if companies sell the software as something it is not. I do not have a problem if they refuse to let me see their source code. Sometimes, this is enough for me to choose not to buy their software, as there are major benefits to having the source, but other times, this is not as important.
Either way, I do not have the right to look at their source if they have not agreed to give it to me, any more than I have the right to look at your email if you would rather I didn't.