And for the individuals who receive the interest, they have to pay regular income tax rates on that income. With dividends they get a different, lower rate.
Nothing is avoiding a tax.
http://money.cnn.com/2013/07/01/news/economy/corporate-tax-r...
Life insurance and disability payouts are typically tax-free because they're paid into with after-tax dollars, but the insureco will invest the funds as it sees fit.