In our house rules for the match with WCL, under which this game was played, it says:

2.5 No Red Rush (Red player can't attack Blue heroes or towns or guarded mines or flag Blue's unguarded town on Day 1 of ANY week using some NEW army (army brought with new heroes, from dwellings, Pandoras, hives, conservatories, portals of summoning is NOT considered as NEW))

There are no stipulations regarding the influence of growth on the outcome of the battle.

Explanation: the red rush consisted of randomly buying some small army of Rampart
the battle itself looked like this:
i_love_jesus - 4 behemoths, 4 angels, 44 wyverns
Aldegir - 2 angels

So, as I understand it, the contentious point is that the new growth from Rampart participated in the battle, but had no impact on the outcome.
I agree that this is not entirely fair, but about six months ago in a similar situation (attacked with growth a zero scout hero with no army) I admitted defeat without dispute.
The rule is broken; if the WCL captain does not agree with the tech loss, then let the captains Neoandy and Wic and the tournament judge Dust decide.