Warcaster Feat tax

[Tanarii]

In general yes, but specifically in this case it is also freely included as part of the action. Both can be true, they are not mutually exclusive things.

You've confused what that sentence is. It is not permission to always make a specific object interaction (drawing a weapon) as free with a specific action (attacking).

It is an example of something that is a free object interaction (drawing a weapon while attacking), followed by the requirement for the Use an Object action, including for a second (not free) object interaction. If you've already taken a free object interaction, then that section is specifically telling you that you *don't* get to draw a weapon with your attack for free, even though it normally would be free. You've got it back to front.