On the contrary it is an easy mistake to make. There are plenty of factions that started off using an ID that wasn't their own because no others were fitting. The SCRA, ironically, being one of them. While the server has moved away from such things, it still makes sense to a newbie to pick the ID that best allows their RP to work.
The proper reaction to this is to explain why, as you did in your post. Throwing pixel weight around the minute somebody infringes on your faction's roleplay and technology on the other hand is very unbecoming of an official faction, who should strive to help new players and point out the faults with the original post instead of threatening them.