To answer your question, Active contacts are contacts that you can email, excluding the company contacts that we create for you.
Your View All number of contacts could be off for a few different reasons.
View All will consider:
I took a look at your account and noticed that there were a few names & emails that were not on any Email List and a list of names that had no email attached. Names without an email address are not considered Active contacts as you cannot send to them. But this could explain the discrepency.
Additionally, If you delete contacts from a list you want to make sure you delete them from the account and not just remove from list:
Does that answer your question? Please let me know if i can assist any further!