My job sends me a similar letter annually for tax purposes, although it's more formal than the one you received. These things came to mind as I read your post...
1. Many employees, myself included, forget how much our benefits cost our employer. I've worked both public and private sector and the costs of insurance is astronomical. When I listen to my colleagues BMW (b****, moan, whine) about how awful our insurance is, etc., I think of that letter and remember that I'm lucky to have an employer that pays that much extra for me. I also remember what the word BENEFIT really means.
2. Health insurance has been rising in the double digits for the last decade. It stinks to have benefit reductions but the choice for most employers is simple: cut benefits or cut employees.
3. Most small business owners I know and/or have worked for struggle annually with point #2. What would you choose? Keep your dental insurance or cut the person who works along side you? (And, for what it's worth, my family has been without dental for 10 years now and it's actually cheaper to pay cash than pay for the insurance. We brush twice a day, use a fluoride rinse and floss occasionally. That's been our experience.)
5. Most small business owners own their business to make a profit. Nothing wrong with that. You would, too, if you owned a business. How long could you lose 10% of your profit annually before you were no longer making a living with your business? Before you had to lay off employees? I know many small business that no longer offer insurance because the costs are too great. For them, the choice is simple, reduce/eliminate insurance or become unprofitable.
4. It's sad that you don't get more appreciation from your boss. But, as another poster said, there are lots of people right now who would love to be unappreciated in your job right now.
So, to your question: what should you think of this message? I look at my letter every year and say, "Wow! Good to know. I'm LUCKY to have an employer who pays an EXTRA $12,000 for me. I could be unemployed, paying COBRA or uninsured." Then, I go to school the next day and work even harder.
In the end, the only person who can make you feel bad about all of this is you. If this is such a raw deal for you, that this is intimidation or harassment, find another job.