The belief that unions have in the last 20 years been a very bad solution to most of the US labor problems they're applied to is not, if you apply your full brain capacity to the analysis, equivalent to the belief that unions should be outlawed.
I'm not sure what you think is supposed to happen when businesses falter. Are the taxpayers supposed to subsidize them?
The point is that the business owner is the one taking the risk of the business, as well as investing his money and making business decisions (including the decision to hire a server). Why should the servers take some of that risk when they are most far away from actual business decisions? why shouldn't, for example, the cook and the cleaning staff take the same risk as the servers?
As an employee, you certainly take a "risk" that your job will not last forever. You may be fired, downsized, or the company may go bankrupt.
Fortunately, since we live somewhere where you can fire, downsize, and go bankrupt, there are companies willing to hire you for some period of time between when they need you and when they don't need you anymore. Otherwise, who would hire anyone if they could never fire them (here's looking at you France)?
The possibility of losing a job is inherent and essential to the concept of employment.
I'm not sure what you think is supposed to happen when businesses falter. Are the taxpayers supposed to subsidize them?