I think by "new pilots" they mean "new pilots at regional carriers," not "new pilots at the majors." Of course, these days, the regional carriers have become the primary path to employment in the majors (it used to be the military), so most airline pilots have to endure a few years of that. The fact is, a lot of people love to fly (at the controls, not in the back), so getting paid to fly for a living is an incredible draw. When you add in the great benefits and the high pay for experienced pilots, you're bound to get a situation where people have to pay some serious dues to break into the majors.
My dad is a retired airline pilot, so I've heard plenty about the airline industry from him. For airline pilots, seniority is everything. Part of it is the pay scale, which as you pointed out, is unbelievably steep: the new guys get paid almost nothing, the oldest hands make (at least) the kind of money people normally associate with lawyers and doctors. However, other things that dramatically effect lifestyle are also driven by seniority, such as scheduling and vacation. The senior pilots are able to schedule themselves for contiguous trips and to be home for weekends. My dad used to pull a trick where, if we were planning a vacation, he would book himself up solid with flying for the first two and a half weeks of the month and then hit his legal monthly limit for flight time, after which he got the last week and a half of the month off without having to take any vacation. New guys, on the other hand, get stuck with crazy schedules where there are inconvenient gaps between flights, leaving them with low ratios of hours flown/days worked. Seniority also determines where you can get stationed: the most senior get to pick their home station, the more junior must select less-desirable stations. The most important aspect of seniority is furlough: least senior gets furloughed first. In a cyclic industry with big swings of expansion and contraction, this is a very big deal. When my dad first got out of the Navy and went to work for Pan Am, they gave him an offer: start immediately as a flight engineer and move up to co-pilot in a year, or wait six months to hire on directly as a co-pilot. Even though he wanted to get back into the pilot's seat as quickly as possible, he chose to hire on immediately and delay co-pilot status. He didn't know it at the time, but it turned out to be the best career decision he ever made: a few years later there was a major furlough, and he was just a few seniority numbers above the furlough line. If he had waited those six months, he would have been furloughed and out of work for several years.
It's not set up this way because of the airlines, its because of the pilots' unions. Part of it is driven by position: Captains get paid more than co-pilots, and pilots of bigger jets (longer flights) get paid more than pilots of smaller jets (shorter flights). Even that is driven by seniority, though: the most senior pilots get the big jets. Some aspects of the seniority system make complete sense: you don't want the airline to use a furlough as an excuse to get rid of its most highly-paid pilots. However, the pay scale doesn't need to be nearly as steep as the unions make it, and if it wasn't so steep then the airlines wouldn't have to lay off as many junior pilots to save a given amount of money.