Foozliquor,
This highlights the difference between home gameroom play and organized event play. You and your family and buddies have every right to play by your own rules and have fun. Just as you and your friends can score and forgive an overstep of the line in bowling by yourselves, or if someone inadverdently knocks the 8ball in during a friendly game of pool. You continue. But I can't think of any league or organized event that would allow these infractions.
As wildcard has noted, on the other hand, at an organized event like even a local weekly draw-your-partner as well as at larger state, regional and bigger events, rules are set and followed. And yes, if you willingly ignore them, there is a JACKASS in the room and it isn't everybody else. Spinning is frowned upon because balls flying off the table delay the game in addition to loose balls flying off due to just the legal shots (not as much) and banned because spinning does not require, or encourage, any kind of skill or ball control, which is one of the measures of organized event foosball. If, however, in your own unique solar system in your own galaxy, tournaments are held to measure and award those having the most fun instead of those with the most skill, then staying in your corner of the universe will prevent problems.
Even in a bar environment, and to a large part because there is no bubble over the playing field, games with a lot of spinning lead to flying loose foosballs that can fall into somebody's drink, or knock it over, or get under someone's feet and cause a litigable or suable fall, or perhaps a fight involving normal bar patrons. Now of course, this can happen even with normal shots, but allowing spinning more than multiplies the chances of errant flying balls. Again, in that environment, the JACKASSES will be the ones spinning at that table. But one can't deny that JACKASSES DO HAVE FUN. They go to jail and do community services more often, but they DO HAVE FUN.
Playing pickups, for foosball, pool, darts, etc.. at a gameroom or bar are supposed to be social and all parties are supposed to agree on rules, so, if spinning is allowed, fine. But don't expect everyone else to question relatively easy to follow rules. The 360 degree before and after the hit are easy to follow, it is easy to see where the foot of the figure used to strike the ball ends up: did it go one turn and go past the original point of striking - just a yes or no. Did it go more than one turn past where it would hit the ball before hitting it: another yes or no.
And if one is playing either friends or strangers outside their home and they request no spinning, as justified by the reasons above, but one refuses to, then there're more than JACKASSES at your table, but players that wish to play selfishly and antisocially. One might have fun spinning, but one shouldn't expect everybody else to have fun the same way... That attitude isn't being a JACKASS, but closer to being RETARDED. Same as questioning why everyone in a bar or poolhall agrees that pocketing the 8ball before your side is complete, or asking why scratching while shooting the 8ball is game forfeit. Sounds like you've come up against anger and resentment when spinning against not just one but several players... Obviously the problem is in their heads and never with yourself, since they all complain about the same thing, all against you. They all obviously are wrong and are ganging up on you since you can't be POSSIBLY BE mistaken. Some people are just dumb, y'know?
This is not to say I agree with other players getting irate when you spin, instead of politely asking to play a non-spin game. This anger is mostly from other players close to the spinners in skill, which means, not much at all .. I find the best thing in bars or other informal venues is when coming up against a spinner, is to exhibit rudimentary ball control and completely annihilate those players, showing how useless it is to play spinning against basic passing and basic shooting skills. And ALWAYS let them run and pick up any loose balls, let them make any new angry acquaintances, especially if it's handguns and hard liquor bible study night at the foos bar.