The starter is interlocked in two ways:
First there is a voodoo AC relay that blocks the start solenoid if the engine is running. It looks at the AC signal from the stator, and when frequency & voltage are high enough, the contacts open to the solenoid, blocking the PB (+).
Second is that the start solenoid is "grounded" through the neutral switch and the clutch switch in parallel. If you're either in neutral or the clutch is pulled in, the circuit to ground is completed.
The issue here is that none of these devices are particularly reliable. The AC sensing relay on my ES350 had a fluctuating reading between 5 & 80 ohms. The neutral switches are historically fairly unreliable. The handlebar clutch switch on mine already had a standing 10 ohms when the clutch was engaged, going to maybe only 50,000 ohms when released, not "infinity".
Yes, if you ground the start solenoid at the toolbox and just have a hotwire back from the start PB you can start in gear. In practice, as an adult motorcyclist with your wits about yourself, it's a non-issue. You trade dubious protection for 100% reliable start solenoid operation. My solenoid went from a half-hearted "click" to a resounding "Thwak!" after there was full battery voltage being dropped across its coil.
The real payoff is stopping for a quick picture or maybe a map read or clothing adjustment. Roll to a stop in 1st gear, key off to stop the engine. Compression holds you when parked, so no fooling with the rear brake whilst balancing. When done, key on, clutch in, hit the start button. Now you are running, already in gear. Just feed in some throttle, ease out the clutch and be on your way.
After 55 years of riding it's long ingrained behaviour as to how & when to use the clutch. As far as starting in gear with the clutch out, that learning curve was hammered flat long ago. If I want to be in neutral, I toe into it carefully & rock the bike a bit to verify, I don't care at all what the neutral lamp says.
The ES is a nice feature. My ES350 puts minimal strain on its bits, your 500 would necessarily be more so. My ES 350 makes barely one revolution before starting when warm. I always start with the kick start when cold. I have a tiny 4AH battery in Molly for now and it cranks it over just fine, remarkably enough to me. Measured DC cranking amps to the starter motor on mine is 30A. If you keep the ES feature, the precautions mentioned here by others are prudent. As I age out, I appreciate the ES option of a warm-engine restart even more. If it does frag, H's has improved bits to sort it with.