My ExDH was a mason, and it was the one good thing about him. I knew quite a few other masons and was allowed a bit of insight into their traditions and internal policies
I know it's a boys only club, but the chapters I have seen are not racist nor classist, and they do an incredible amount of charity work (the one I knew about provided significant financial support for a womans crisis centre), and they do help each other out. One of my friends dad was made redundant and through his masonic connections his family was provided for, for 4 months while he found another job
I think it's a good thing, and if you're that worried, why don't you look into joining one of the "sister mason" groups?
Good post. We have nothing but positive experiences since dh joined, my dad was one too but different lodge. It's mainly charity work and they raise an incredible amount, iirc it's only the national lottery that raises more. Dh has never been secretive, nor has my dad, maybe it used to be but ime it's not now.
It costs £100 a year subscription and at dh's lodge the meals are about £20 and you don't have to go to many - I think he goes to about 3 a year.
It's dh's 'thing' and I am not interested at all so never go to any of the evening do's. I meet up with my friends every month or so and see dh going to his lodge as the same thing, don't think he has as much fun as I do as he sees it as an extention of work.
I think it's easy to ridicule things you know little about - do a bit more research OP and take it from there. Is your dh keen? Dh joined purely for net working and making contacts and career wise it was been very good for him.
Secret codes etc - it's only like Scouts dibbing and dobbing or whatever they do, nothing sinister! I know all the words as I had to test dh 
My friends dad was looked after by them when he was orphaned, sent him to a masonic boarding school, they do look after 'their own.'