I’ll give you a really simple analogy. Before level scaling, you had zones with mobs that were much higher level than you. Depending on the mob, zone and of course your level, they were impossible to kill and/or would 1-shot you. Did you routinely go into those zones to explore, quest, level, loot, etc.? No. I’m sure you didn’t because you knew the zone was too high for your current level and the mobs there did not care whether you belonged or not.
Warmode is very similar in the sense that you can avoid it just like you can avoid going into zones you didn’t belong in. Like others have said, you opted to enter a more dangerous zone (warmode) in exchange for a small boost. A boost i might add that was specifically noted to compensate for the additional downtime you might experience running to and from the graveyard.
If Blizzard did not intend for low levels to be killed by high levels, they would have made it as such. As a matter of fact, they did b giving you the option to enter and exit warmode whenever you please.