The Robinson-Patman Act of 1936 was called "the anti-Sears, Roebuck law" because it was directed again this and other chains that charged lower prices than smaller retailers could match.
For a long time, there were so-called Fair Trade Laws designed to keep low-cost businesses in general from charging low prices that drive high-cost businesses out of business.
Fortunately, enough sanity eventually prevailed that Fair Trade Laws were repealed. But the emotional needs that such laws met were still there, and today they find an outlet in hostility to Wal-Mart and other "big box" stores-- especially in San Francisco and other bastions of the liberal left.
People have every right to indulge their emotions at their own expense. Unfortunately, through politics, those emotions are expressed in laws and administrative decisions by people who pay no price at all for indulging either their own emotions or the emotions of the people who vote for them.
That is why the Constitution tried to erect barriers to government power, of which property rights were one. But, once judges started saying that "the public interest" over-rides property rights, that left politicians free to call whatever they wanted to do "the public interest."
Neither economics nor property rights are too "complex" to understand. But both get in the way of willful people who seek to deny other people the right to make their own decisions.
Anyone who doesn't like chain stores is free not to shop there. But that is wholly different from saying that they have a right to stop other people from exercising their own freedom of choice. That's not too "complex" to understand.