McDonalds claims their customers like the coffee at a higher temp (175-180) since they often commute and don't drink it for a while.
I guess you don't commute either. Most people who get coffee at a drive through start drinking it immediately.
From the article;
Other establishments sell coffee at substantially lower temperatures, and coffee served at home is generally 135 to 140 degrees.
Further, McDonalds' quality assurance manager testified that the company actively enforces a requirement that coffee be held in the pot at 185 degrees, plus or minus five degrees. He also testified that a burn hazard exists with any food substance served at 140 degrees or above, and that McDonalds coffee, at the temperature at which it was poured into styrofoam cups, was not fit for consumption because it would burn the mouth and throat. The quality assurance manager admitted that burns would occur, but testified that McDonalds had no intention of reducing the "holding temperature" of its coffee.
That is an admission of guilt and recklessness by McDonald's,
They finally changed their policy
Post-verdict investigation found that the temperature of coffee at the local Albuquerque McDonalds had dropped to 158 degrees fahrenheit.
Similarly, I also don't blame knives for being "too sharp" when I drop one on my foot
You miss the point that a sharp knife will not cause damage if used correctly. Coffee at 180 degrees would burn the mouth of consumed.
This might be one of the reasons that Tim Horton's actually puts in the cream and sugar so you don't have to on the car.