I deliberately avoided saying that and was giving a general warning that these guys often get things wrong.
However, in your specific example it's probably not black and white. If the money is in a simple bank account and you have a statement from 31/12/2023 showing a balance, then that balance should not be taxable if brought into Thailand. If however that money gets added to in any form (interest, further deposits etc) it could get messy.
If the money is held in pensions, stocks or other financial instruments then all bets are off, and given what we read or watch the taxman could claim some of it.
I'm a firm believer that the taxman is not interested in us run of the mill foreigners living here on retirement or marriage extensions, but that could change down the line.