This problem is overstated because modern devices from TV to radios to phone chargers all using switches supplies. With a good design there is no problem.
It's only overstated if you don't have a noisy switching power supply like the SEC-1223.
Not to push the matter, but just because you have one that is noisy doesn't make all of the Samlex supplies bad. The reviews section here has the score of 4.4 out of 5 for an average. That's pretty good--for what you claim is a bad, noisy power supply.
There have been quite a few mods made available for the Samlex SEC-1223 on the internet over the past few years. I haven't heard of anybody exactly saying it's a bad PSU, but some people have identified and cured RFI caused by design choices (flaws or cost cutting) in the unit.
I have had mine for years now and it has always been reliable, however like others I have noted a drop in voltage when it is under load.