I'm not aware of a welding process that is safe for humans without at least a dust/fume extractor. That and a respirator with the appropriate filters for the application that fits under a welding hood is basically standard equipment even for hobby welding in my opinion. Also hex chrome is a particulate, not a gas, and tig welding uses solid rods (not flux core) and a much smaller heat affected zone so it's already better in that area AFAICT, but I'm not an expert in this area.
As far as particulates when welding go you should watch how careless people are when they grind their tungsten electrodes containing all kinds of dangerous additives with their respirator around their neck because "I'm not welding so I don't need it".
So yes, this is good advice. We should all think more about the things we do, even when working on home improvement projects and mundane stuff, that could end up damaging our lungs.
This gave me an idea. Have you considered buying a used higher quality rack and modifying it? Might save some time and get you what you want with less new material, and sort out some of the harder parts to fabricate because they'd be done already, possibly only requiring a little bending to align with your eyelets. Plus you'd be saving something from someone else's scrap pile.
Around me there are a few community run used bike part shops. They typically have lots of racks and other parts kindof organized into piles or boxes by type. I can usually find something close to what I need if it's not too specific.