Most do not celebrate because it never occurs to them. They are wrapped up in their work or school and simply never think about the holiday, or they do not know a veteran and therefore feel no personal connection to it. Understandable as that may be, I personally do not believe attending memorials or ceremonies is necessary to celebrate the holiday. The holiday’s intention is to show gratitude and appreciation to soldiers and that can be done in a number of ways. Donating or volunteering to charities/organizations intended to provide assistance for veterans is one way. Some families have special dinners with relatives that have served. Simply thanking or chatting with a veteran you know is great. Not everyone has the ability to attend local celebrations, but there are so many other ways to observe the holiday.
They deserve respect in the same way all people deserve respect. No, not every soldier is honorable, but that should not taint the view of the entire military in the same way that inept doctors do not taint the positive view of the medical profession. I never believed in so-called “hero worship” for soldiers, but on the other hand, there are few soldiers who desire hero worship. They don't ask for giant banners or grand displays of fireworks. Perhaps you don't believe soldiers deserve respect, but they protect your right to have such beliefs.