Security is a necessity, and the personnel employed to ensure it are not generally in the level of high IQ.
At the very least, the training schools they attend seem not to have a subject of tactful approach written into the curriculum.
If they did, they would not create the response most of us would have when aggressively accosted by them.
Like any police force, they are demanded by a civilised society, and fall into the category of "necessary evil", but that does not demand they leave what little grey matter they have at grade 6, and act as if they are Hitler's stormtroopers.
