There are various views among apostolics on the question you have asked. As far as how apostolics feel about the pagan roots of most holidays, I believe most would be included in one of the following three categories:
1. Those who have researched the roots of the pagan holidays and do not engage in or celebrate those holidays because they do not want to be associated with pagan practices.
2. Those who are aware of the pagan roots but do not feel they are engaging in pagan practices when they celebrate these holidays.
3. Those who are unaware of the pagan roots of most holidays.
The practices of apostolic people vary widely.