IMO What people do in their seats on an aircraft or in the lounge is their business providing it does not impact on others but I would argue that dangling your bear feet off the edge of your seating area or sticking them up on a table, where others later might be eating food, is very much affecting others. If my feet are anything to go by the smell alone can be invasive. It is all about respect of others and that is often in short supply, particularly when travelling.

I don't have too much of an issue with shoe'd feet on the bulkhead but IMO bear feet in an aircraft or lounge should not be allowed.

Here is an interesting take: How hygenic is kicking your shoes off in the work place?