People are entitled to build whatever they want on their property. As Silicon Valley is ruled by rent seekers who make building illegal, people have every right to complain.
"Rent seeking" is a specific term in economics referring to people who seek to extract wealth from the economy without adding to it in any way, e.g. "make building illegal" in order to force up the value of their own property.
The term is somewhat dated, but the usage makes sense in context. Historically there has been a noble class awarded privileges via mechanisms external to the market that leveraged those privileges to extract revenue from the market. Generally this consisted of renting out some right like the right to farm certain land or draw water from certain wells or dock ships in certain harbors. From this we get the modern economic usage of the term "rents" to mean the additional cost someone can charge for something due to their exclusive or semi-exclusive ability to provide it. Think patents, copyrights, monopolies, trade secrets, and ownership of scarce finite resources (like land in SF). From this comes the term "rent seeking" to describe the behavior of obtaining market privileges through means external to the market. This (mostly) consists of trying to influence laws to be in your own favor, like patent owners trying to get patents extended or homeowners opposing upzoning.
You're welcome! I went down a wikipedia black hole on economics a while back. The most memorable term I learned was moral hazard, which also sounds confusing.
No one's proposing to build a sewage treatment plant on this land. It's just more housing, in a city where people go without a roof over their head because it's too expensive. There's no "nuisance" here, only landowners trying to assert rights over their neighbors' property.