Don't have to be so rude about it, just because they are new doesn't mean they don't have knowledge to share
I agree people shouldn't be dismissed, but to be fair, Diane wasn't discredited for being "new", she was discredited for sharing an uninformed opinion. God knows there are a lot of people offering bad information and the stakes are too high to let it go unchallenged.
This is a topic I have researched extensively and consider to be my second option (the implausibility of it appearing 'accidental' is it's biggest drawback for me, but its lethality is unquestionable). The biggest disadvantage to the 'Detergent' method is the danger to first responders, but with careful planning and execution, this danger can be virtually eliminated. If the mixture is carefully measured and the reaction is permitted to progress in a confined space, lethal levels of hydrogen sulfide (h2s) are reached relatively quickly. The person who has chosen this method can place notices in proximity then alert emergency services before entering the confined space. Professional first-responders have protocols to follow in the case of h2s and will know how to avoid incidental injury. At lethal levels, the gas is so fast acting that loss of olfactory sense usually occurs with the first inhalation. The second breath is usually enough to produce unconsciousness. The gas is as toxic as hydrogen cyanide and the effects are irreversible. At concentrations above 700ppm, unconsciousness is immediate and death occurs in 1-3 minutes;
at concentrations over 1000ppm, death can be instantaneous. The rapidity of effect is a big reason why it's on my list, and if I use it my intention will be to create the reaction in a confined space and leave it for a few minutes to let the levels rise to over 1000 ppm, then I will re-enter and seal the space holding my breath, sit down and breathe deeply. The end.
No method is fool-proof, but careful research and planning helps prevent one ending up feeling and looking like a fool. A person telling other people not to use a method simply because he didn't have the understanding needed to execute it correctly is just like me telling someone not to drive a car because I've wrecked mine. Living (and dying) are a little like going to school....if you don't do your homework, you might end up looking stupid, and if you do, you've gotta take the shame.