It's a safety net, thinly disguised as insurance. Hence, the federal government extended unemployment insurance out to 99 weeks at the height of the recession. I've never heard of an insurance company doubling the payouts to policy holders.
You're (understandably) getting revenue streams mixed up. Payroll taxes only go to Social Security and Medicare, and the payroll tax holiday was a stimulus measure during the recession. Many states ran out of funds for unemployment insurance, which resulted in the federal government funding it and extensions, an act that some die-hard Republican legislators decried because they didn't want to spend the money without offsetting it somewhere else. There's a separate tax for unemployment insurance. There is no "slush fund."
Sorry, but SS is another safety net, thinly disguised as a retirement program. SS also covers people who are disabled.
Again, vastly incorrect, though understandably so, due to the aforementioned "thin disguise" part.
The initial law dedicates payroll taxes to SS, and it is (and always was) "pay as you go" -- as in, the payroll taxes collected in 2005 were spent on benefits paid out in 2005. There were surpluses for decades, and those surpluses were by law loaned to other parts of the federal government.
In reality, a tax is a tax is a tax, and how you spend it doesn't actually matter where the revenue comes from. In order to trick people into thinking that SS was a "retirement fund," rather than a standard tax, they came up with the dedicated payroll tax, which disguises the realities.
By the way, every penny of those intergovernmental loans has been repaid with interest, and there is every indication it will always be paid. (Even if the Treasury Department had to straight-up print money, it will be repaid.) There was no "raiding." The trust fund is still solvent. The current problem is that life expectancy is at least 10 years longer than it was in the 1930s, and revenues aren't keeping up with payroll tax income. Thus, SS benefits are now drawing from the trust fund.
We will have to increase revenues and reduce expenditures in order for SS to continue. The thing is that Canada's Social Security is much more expensive than the US, relative to the two nations' GDP. SS is a significant chunk of Canada's GDP, and a tiny sliver of the US's (13.3% vs 0.077%). This in turn results in a much, much lower rate of elderly in poverty in Canada than the US (7.8% vs 24%).
It is critical to note that OAS and GIS -- over half the cost of those safety nets -- are funded by general tax revenues. For some inexplicable reason, it does not occur to Americans that our nation can do the same for Social Security. Did I mention the whole thin disguise / illusion stuff yet?
Below is the SSA's comparison of SS in the US and Canada circa 2008.
The Canadian Safety Net for the Elderly