The silicone earplugs I'm familiar with are like a moldable putty, not gel-like. Is that what you are talking about?
The restrictions for carryon bags is for any liquid or gel that will not hold its shape when removed from it's container. The moldable silicone earplugs would not fit that description and can be packed in your carryon without issue. If the earplugs are silicone gel inside an outer layer, then they would have to go in your quart baggie as a liquid.