Actually, you have never mentioned any word about the difference between Active Dual-Sim and Stand-by Dual-Sim, which makes it also really unclear about which type of Dual-Sim phone you’re talking about. Hence, you’re just frightening the people without giving out any further details and explanations.
You have never mentioned, that Stand-by Dual-Sim phone works with one transceiver only and just enables you to easily switch between two sim cards. One transceiver can’t emit double radiation, as the antenna is one — and the only actively reaching out sim card will always be one of two.

I’m myself quite picky about radiation topics, but you’re simply lacking information, therefore — misleading people.