I think "TLR" in Bontrager-speak simply means "tube-less ready". They apply it to a whole family of wheels ranging from low-spoke roadie rims to higher spoke-count mountain-bike wheels.
Spoke-count is not the only factor in wheel strength, but generally,
other things being equal, a wheel with more spokes will be tougher, which is why you see higher spoke-counts on MTB wheels, and low spoke-counts on wheels intended for riding on smooth roads. Essentially, your weight, and the weight of all non-wheel parts of your bike, "hang" on the spokes at the top of the wheels, and sharing that over more spokes gives you a greater margin for error. There is also the issue of lateral stiffness, and generally speaking low-spoke count wheels are less stiff that wheels with more spokes (again
other things being equal). The main driver for low-spoke wheels is aerodynamics, which is chiefly a racing concern.
These are rather abstruse points for a transport cyclist, but commuting can be hard on wheels. Most of the ride will be on smoothish tarmac/concrete etc. but it is not always possible to avoid areas where the surface has broken up, and sometimes you have to bunny-hop a kerb, or take radical avoiding action. My bike has 406mm wheels (the same size as most BMX bikes) with 32-spoke Velocity Aeroheat wheels. It is probably a bit
over-built, but so far the wheels have stood up well.
WHY would they put a RACE ready wheel on my comfort bike that I am riding everyday to work to lose weight???????????
Leaving aside the probability that they are just a bunch of pricks (which seems high given their comments on your weight), there is a significant problem with bike-shops in Australia focussing very strongly on cycle-sports, and this might be true in the USA too. There is only one bike-shop in Sydney (as far as I know) that
specialises in transportation cycling. It is fair to say that this reflects the emphasis of the cycling industry generally, at least in the English-speaking world, and it leads to poor choices being offered to transport cyclists.
For example, there are plenty of "comfort bikes" on offer that are built on frames better suited to fast road riding than commuting, because manufacturers like to share the frames across a wide range of bikes. The tight clearances at the top of the forks, and sometimes the choice of brakes, don't provide clearance for sensibly-wide tyres, and the bikes are sold with narrow wheels and slim high-pressure tyres, which give a harsher ride, and require closer attention to maintaining pressure if you want to avoid pinch-flats. Then, to address the harshness, they fit suspension forks, adding an additional weight and complexity that would not be necessary if sensible wheels and tyres could be fitted. Unnecessarily high bottom-brackets on transport or comfort bikes built on sporting frames is another example of a "sport" feature being imposed where it is not fit for the purpose, and it can even lead to knee injury if the rider is not clued up.