There are some casual viewers who will never get and enjoy anime because they feel that anime is a bit rebellious from what they are used to. There are also some people who will not get why anime shows need to last for a long time. A lot of the usual cartoons can only last for a short period of time.
Some anime shows can last for a full decade. The storytelling of the Japanese anime series can also be hard to understand for someone who has never watched any other show in the past. Those who have watched anime series for a long time may also feel this way when watching new shows.
Many people do not find anime to be weird but if you are really young or old, then japanese anime may seem weird to you. The simple answer is that people who are not the right age may find Japanese culture and mannerisms commonly found in anime to be a little out of the ordinary.
It is Japanese culture to make anime really over the top sometimes but other times it can be quite serious and understated and powerful. I recommend that anyone who thinks anime is weird continue to explore more anime and maybe ask other people you know for recommendations that fit your style. The world of anime is an art like any other art and not all of it is for everyone's tastes.