It's interesting to read this thread. Thanks for volunteering, OMC, and thanks also to those who've posted real-life instances.
I think the issue gets twisted by those who see the Masons as generating favouritism - which I'm sure it does to a degree, having started life as an exclusive trade guild - where the real problem is the high proportion of decision-makers who are prepared to abuse network relationships on a quid pro quo basis. The same people would seek out powerful networks whether this one existed or not, and would seek to set up similarly biased exchanges of favours.
Since freemasons exist and have, for centuries, counted the world's most powerful men amongst their numbers, they're the obvious network of choice for such (male) people. The fact they gravitate there and, naturally for them, seek to promote the closed favour bank, makes the Masons a great network for power brokers. If there were no freemason network, they'd be doing the same through their golf club (as, indeed, they do); their church; dining & drinking clubs or the mafia.
Every society is only the sum of its members. Outlawing the freemasons would fail, even if it were desirable. I do, however, think it would be better for the movement's image if it published details of its membership structure & numbers, finances and activities. It could, as a private club, require disclosure of its more senior members.
The fact that it still resists transparency does seem to indicate it has plenty to hide. Of course there are conspiracies! They make the world go round. But they shouldn't be allowed to determine public policies and their execution; not in this day and age. If Masons want to insist they don't exert undue influence, they should prove they mean it.
Since they won't, I draw the obvious conclusion ... and would like to see some sort of legal compulsion to disclose.