Malicious Communications Act 1988, section 1, "deals with the sending to another of any article which is indecent or grossly offensive, or which conveys a threat, or which is false, provided there is an intent to cause distress or anxiety to the recipient".
Please tell me, if it wasn't the kids intention to cause distress however naive, what was it?
Let be me clear here, If someonewants to burn a poppy in the privacy of their own home, then let them get on with it.
When you make views such as this public, either for personal ego stroking reasons, or just to kick up a sh*t storm for the hell of it, then thats where you cross the line into wrecklessness and stupidity that could give rise to violence.