First of all, I think 'going backstage' can mean different things - backstage tours, seeing dress rehearsals or programs that allow people to see "a day" in the life of a dancer. The article above, it seems, is referring to backstage tours, but others have brought up the wider range of potential backstage activities.
The tone of the article is a little unpleasant, though it is not meant for the general public, so I can understand. But, it's worth remembering that what can be mundane for one person is exciting to another. While people who's everyday life is 'backstage' may see nothing special about it, the rare peek behind the curtain is often fascinating for audience members. And for that reason, tours and the like may draw in more people to the ballet.
My feeling is that backstage tours can be a real eye opener, if they are done properly. Getting to see the NYCB wardrobe room at the NYS State Theatre was fascinating - viewing the costumes up close really allowed you to see the details and to appreciate the work that went into them. And also to be able to see the theatre from the point of view of the stage and get a feel for the dimension of the stage.
But, the business of putting on the performances has to come first, so tours need to be well-coordinated with the company so that unfortunate experiences, like the one mentioned in the article above, do not occur. That means communicating with dancers, stagehands, lighting designers, ADs and other staff to find out what times work best, and not being afraid to limit or stop tours during busy periods, such as the weeks before a big new production is debuted or towards the end of long seasons when people are tired. And getting feedback - were the tours disruptive, would a different time better, would fewer be better?
I have more mixed feelings on dress rehearsals - they are trickier situations, but I have to disgree with Jeff. I would NEVER review a dress rehearsal, but find watching them very helpful because it's really hard to review a new piece, especially a full-length ballet, on one viewing. There's often so much going on and I like to see a ballet more than once so I can focus on different things each time and see a piece from different angles. I'm not expecting perfection - fantastic performances can follow disastrous dress rehearsals.
And I would agree that discretion needs to be exercised in allowing people to watch....
Many companies do provide some opportunities to watch dress rehearsals - often as a perk of being a donor. Of the companies I'm familiar with, ABT, NYCB, Royal Danish Ballet, Scottish Ballet and Northern Ballet Theatre all open some rehearsals to viewers, either donors, school groups or other persons.
But, I do get uneasy with the 'open dress rehearsals' that companies like ABT and NYCB do for their donors - but interestingly enough did not get the same feeling with European companies.
And I think the blame falls largely on the attitude and behavior of the US audiences. In part, I think it's because there is much more money associated with these opportunities, but also because, frankly, many Americans don't know how to behave at a performance. Despite written and oral reminders about appropriate behavior, I've witnessed more appalling behavior in open dress rehearsals than at many actual performances. At ABT, I believe, the rehearsal director actually had to stop and yell at the audience to be quiet because of the noise. Now that, to me, was a sure sign, that it was time to close the open rehearsals. But, that would never happen because people want 'rewards' for donating money.