@Shpalman
For starters, the Catenaccio is no longer in use. Catenaccio involves man-to-man marking, which is no longer used in favor of zonal marking. Even "parking the bus" is zonal marking, not man-to-man. I believe the last team to use the Catenaccio was the Italian national team sometime in the mid-2000's. Catenaccio was actually very highly respected, as it helped Italy win the 2006 WC, and made Serie A one of the best leagues in the world back in the 90's and early 00's. Unfortunately, the style just wore off as football progressed, so we really won't see a full Catenaccio system anymore.
Parking the bus is looked down upon simply because it's a desperation act. It's quite literally "desperate" defending, as it involves throwing every man (except one) behind not only the ball, but behind the 30 yard line to your goal as well. This type of football is rather, um I don't know how to put this, but "disgraceful". I see no reason to park the bus unless a team is down to 10 men. A red card to your team against extremely superior opposition would give you the ideal (and theoretically correct) time to park the bus (e.g. Chelsea against Barcelona after Terry was sent off). But in general, it just takes all the excitement out of the match, as one team will have 90% possession, and the other team will just get the ball and kick it out, not bothering to counter-attack or set up any form of shot on target (because only one man will not be part of the "bus").
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