There are several reasons why I did not make UMC units trainable by buildings in EE:

1) that would override functionality of the base game which goes against UMC's core principle to not alter any vanilla files but only add new content
2) by overriding functionality of the base game, UMC users wouldn't be able to play scenarios made without UMC, as it currently stands, UMC users can play any scenarios made with or without UMC
3) I don't think it would be fair for me to arbitrarily decide for users which buildings should be able to train which units, users should have the freedom to decide that for themselves
4) the principal purpose of UMC is use by scenario designers and modders
5) the ultimate goal of UMC is to have several factions built into the data structure which will be able to train their own units, not all UMC units will be incorporated into this project
6) it's pretty easy to make units trainable from whatever building you want using the guide below

See this guide for how to make UMC units trainable from buildings of your choice.