As dudeious said, you must only be present in the alliance at the time of matchmaking in order to be included in wars… Then be back before the war itself starts…
See this thread for a full-breakdown on how matchmaking works & a more in-depth discussion on the topic.
Alliance Wars Matchmaking (Discussion & Developer Response) MASTER
Please also note that “naming and shaming” is against the #forum-rules so your post has been adjusted.
For complaints & venting feel free to make use of this thread instead:
War matchmaking strikes again