It is a ripoff in the meaning that the premiums are not strictly associated with the odds of having a loss and the cost to replace or repair. I got an insurance when I bought the house for about 950/yr. It has increased over 3 years to about 1400/year. Has the cost of rebuilding a house increased by at least 40% between 2008 and 2011 (since it has administrative and margin included)? Nope. Obviously I dumped them and shopped around - which I may have to do again as it has gradually increased from about 1000 to 1300.
Look at auto insurance - try to get one a day before you are 26 and the day when you turn 26. Vastly different premiums. Does anyone suddenly become a much safer driver in one day? Nope - ripoff, while younger drivers DO cause more damage, every insurance company does it so it's "fine". You also must - by law - carry this insurance if you're driving - so no real "I'm willing to take my chances" option.
You insure high value items because you can't afford a total loss - but that doesn't mean it's not a ripoff.
You may buy life insurance because you want to be 100% certain that your family will be covered at least financially.
But most single-purpose insurances are a ripoff. And if you can accept an occasional loss, you're way ahead of the game overall.
Try to rent a car and they will scare you with buying extra insurance for "only $20/day" even though your own insurance covers it (but many get scared and wouldn't want to pay $500-1000 out of pocket in case of an at-fault accident even though having the accident in your own car would cost exactly the same). And then Visa gives rental insurance automagically.
People get scared into buying $10,000 whole house generators (you wouldn't want to be without heat the middle of the winter) - although $100-200 will get you a nice room at a nearby hotel...
Insurance is generally based on fear... bought that brand new $2k TV? pay another $300 to insure it for 2 years, it's really expensive and you wouldn't want to lose it. Well guess what - the factory warranty is 1 year, the credit card makes it 2 and it doesn't cost a penny extra. And for $500 you can insure it for 4 years... well in 4 years you can buy a better model for $500.