When I go to a country where the social convention is tipping, I tip.
Even if it isn't against the law, there's no point in being overly hostile socially, unless you are prepared to put up with that flak.
You still have the right to a penny or no tip if the service was horribly unacceptable.
I don't like tipping, especially when I can't guarantee that my tip is going wholly to the server, and even then it befuddles me how they have to share the tip with kitchen staff etc, so it seems those staff aren't getting paid "enough" either. It's also pretty confusing.
That linked article seems to prescribe a stiffer / higher set of tipping rules that I'm used to, e.g. except for New York, I was used to 15% base everywhere. So now it is 20% everywhere - really? - or then again this is the Washington Post, so...
Counter staff at fast food and the like never got tipped. There was a tipping jar, but I thought that was more an excuse for people to get rid of shrapnel they didn't necessarily want. That jar got shared with everyone.
I have to admit that when I'm in the USA, I feel uncomfortable because I forget who to tip and how much to tip. It doesn't matter how many sets of rules I read. Then, I feel bad if I stiffed someone, and it's not got to do with that person not getting paid enough or whatever. How much someone is getting paid never comes into consideration when tipping.
Anyway, this isn't the first thread on this kind of thing. Definitely isn't the first article on the topic, either. In fact, one could viably argue that both are being done to the death.