Appetizers at cocktail hour???

"Is it necessary to have small bites to eat at cocktail hour" is asking if it's necessary (granted without the correct punctuation), which is very different from making a statement that it is necessary.

The reason bars are required to serve food with alcohol is because food in your stomach makes the alcohol absorb at a less rapid rate. Alcohol is essentially poison, and without anything else in your system the alcohol is absorbed faster. It's the same reason why you aren't supposed to take many medications on an empty stomach. Serving guests alcohol without any food options is really irresponsible, IMO, and a great way to make your guests sick or drunk. You don't need a full platter of expensive appetizers, but you need something.

The rule of thumb I follow for any event with alcohol present is to at least have something for guests to snack on so the alcohol doesn't hit as hard. We went to a wedding in August and they had open beer and wine and SO LITTLE food...it was awful. We ordered Uber Eats as soon as we got to the hotel as we were STARVING and still tipsy lol

If you're serving alcohol, then food of some sort is required to be served at the same time for liability issues.