I'll agree with him but for some different reasons.
First of all, a cartridge is just a little brass cylinder to hold primer, powder and bullet. There is nothing mythical about the variations in the size and shape of this brass cylinder.
Now, the 38 Special is a big enough brass cylinder for a handgun cartridge. Witness all the evidence that the 9x19mm is not just "enough" but is ideal because it is also not larger than necessary, thus providing magazine capacity, ergonomic grips, and low-recoil.
The 9x19 is a higher-pressure cartridge, but the pressure limit on the 38 Special is arbitrary. The limit on the +P is also arbitrary, as evidenced by the 38/44 which was as far back as the 1920's just a 38 Special inserted into an N-frame revolver that gave people the confidence to load it to pressures closer to 9x19. Today, the only difference between a 38 Special and 357 Magnum is a little extra length of brass at the case mouth that does nothing to change how much pressure the cartridge is good for. The point being, a 38 Special loaded to good pressure can offer "more" than a 9x19, more than a 9x21, more than a 357 Sig, more than a 9x23, more than a 38 Super. It is in fact nominally a 9x29R case, which means it can be hot-rodded pretty damn well. It can also be loaded down to the lowest levels of effectiveness somewhere near 380 or even less. It is rimmed, being most suited for revolvers, and I'll claim why that is "the best" also.
What we have so far is a cartridge that can be loaded from near-357 Magnum levels down to old-lady levels and it's best suited for revolvers. Revolvers are "the best" because of their simple manual-of-arms and because they're offered in big steel frames that take a lot of recoil. Whether it's loaded hot or "not" a heavy revolver makes the cartridge more manageable for anybody, stud or geezer. We always hear the argument for 9mm, that besides having "enough" effectiveness and more capacity, it's easier for everyone to shoot well. Well, if a 9x19 in a twenty-something-ounce polymer gun has empowering manageability, then a similar load in a big steel revolver is even easier to shoot well. If the capacity thing is the most compelling case for the 9, then it is for the 38 Special also since it is the chambering of the highest-capacity revolvers (other than 22LR). The Kimber offers 6 shots in a tiny revolver that nullifies any advantage to the 327. Then we have 7 and 8-shot revolvers for the 38 Special unsurpassed by any other cartridge.
Bigger caliber cartridges will always recoil more for similar terminal performance. You may enjoy them in the interim, but as a new shooter, the 38 Special is better, and when you get to be a geezer, the 38 Special is better. Might as well just stay familiar with it since it will be there in the end. The larger caliber will require a heavier bullet for the same sectional density and that will result in more recoil. No doubt they offer "more" terminal performance, but the evidence around the 9x19 suggests that may only be desirable for big game hunting or something else untypical of handgun use. Bigger calibers will also reduce the capacity of what is the largest practical cylinders or magazines. Smaller calibers like the 327 or 30 Super Carry have not proven to be meaningfully advantageous and the market has not produced guns that make these cartridges compelling propositions. Cases shorter than the 38 Special like the 9x19 are just fine for pistols with the magazine in the grip where that becomes a necessary compromise. Longer cases like the 357 have little meaningful difference. Because good revolvers today will always be reamed out to 357 chamber length and its really the only way to get standard-pressure factory ammo (as opposed to low-pressure ammo), I would just choose 357 guns and brass, but the difference between 38 and 357 is just hype. If we stretch to 357 Super Magnum, Maximum, 350 Legend and so on, then they become impractically long for the most common revolver frame sizes and they offer no real advantage in the purposes for which handguns are most popular.