I’m calling BS on this unless you’ve got a link. I can think of two Stöckli dealers off the top of my head who own infra red waxing equipment. I seriously doubt they’d invest in it if Stöckli said not to use it on their skis.
Maybe
@LindseyB can settle this at least for Stöckli.
I personally am not aware of any official statement from Stockli regarding infrared, but I personally recommend being careful with both infrared and irons. You can overheat a ski with either when trying to rush the process.
In short, always use wisdom and caution when using heat around any and all skis.
My unsolicited take on wax:
The idea that wax is penetrating a base is ski culture superstition and marketing silliness. The material is the same as milk cartons. It is not porous enough at a molecular level to be penetrated by wax/base treatments despite what people want to imagine.
A fast base material is the biggest factor in glide. (Typically graphite content and structure are biggest factors here). Base treatments are for supporting the job of the base. A cheap base can be helped by good base prep, but it will never be able to substitute for a high performance base.
An iron does not make wax magically penetrate the surface, however it will provide great consistency when adhering to structure.
Cold wax being harder requires more passes by an infrared and more heat transfer with an iron. More passes means more internal heat. So be careful as with any heat source regarding skis.
For most of my quick prep for single day use I turn to roto brushing on Fast Stik and it works pretty well. When I have time and want 2 to 3 days depending on the snow crystals and skiing I pull an iron out, but it has been a long time since I pulled my iron out. For slush I use to use Dominator Butter, I now use fast Stik warm as it does the same exact thing for half the material cost. I strongly recommend either as it's not only fun to go really fast on wet snow, but also because hitting the brakes in wet snow can be a major skier hazard and "wreck" all the fun. The only downside is that both of these warm waxes have to be reapplied every 2-3 (6k-10k ft.) runs because they are so soft and they peel so fast on the hard slush crystals. But very worth it.
No one option is perfect for every scenario, I believe this is why we have so many different options for base prep. Many work well and all have their pros and cons.