The top 1% are almost all business owners, and taxing them would give them less capital to expand their businesses or start new businesses. Hence, leaving them unable to hire additional employees to work in these new/expanded businesses.
Rich people dont just sit on their money. They invest it to try and make more. These business investments provide jobs to Americans.
By taxing them, you reduce they money they have to invest, resulting in a hiring drop which therefore increases unemployment. Or at the very least, does nothing to reduce it.
But there's also the opposite coin to this argument, let's say we shift some of the tax to top 1%, and take the extra and drop it to the bottom 10% of people. Those people tends to be very poor, they use almost 100% of cash out every month. Now, this extra spending gets to the pockets of rich business owners, creates market demand and with increased demand for their products, business open new factories to satisfy demand. This money also creates jobs, you spending indirectly creates jobs for you. In short, no matter where you drop the money it gets into the economy, resulting in jobs.
I personally think, both ways work at different times. In normal times when consumer demand is high, demand drives business, there's no need to pour money into consumer end rather you can give some cuts to businesses to ease burden in opening factories etc. Even a low cost loan would be enough for business.
But during recession/depression, there's no consumer confidence, no demand, giving money to businesses don't solve the demand problem. Businesses will not spend money on new factories with that extra money, reason is simple, they follow demand, they are not going to take a "make these merchandise and they will come" approach. In this case, some extra money to the lower end of spectrum would help spur demand as well as artificially creating job w/ stimulus. Thus a few rounds of deficit spending on business infrastructures like railroads, high ways, new shopping mall etc. would create jobs while the business sector is temporarily paralyzed. Along with some tax rebates will boost consumer confidence. then turn around and do business tax cuts when consumer demand is higher. This 1-2 punch should be effective.
The natural switching between Dem/Rep in election cycles essentially achieves this 2-ended boost to kick start the economy in a recession.