The Ukrainians are flying drones filled with explosives into Russian refineries and we still don't think it was just the Ukrainians taking out the Russian gas pipeline?
They're in open war with Russia, are openly attacking their resource infrastructure, and are frequently posting excellent high quality footage of it.
Taking out the gas pipeline and then not using the attack for propaganda doesn't fit either their situation or their actions.
Your broader point is correct though, admitting to blowing it up would be bad press to any party.