Actual gerrymandering isn't. That's why the courts get involved and sometimes re-draw lines.
Getting as close as you can to gerrymandering without crossing over is legal. Kinda like every other thing that's illegal.
Fundamentally, the problem is that designing systems to produce votes in a representative democracy is REALLY hard. There are checks and balances, though.
Gerrymandering was okay before it wasn't. In other words, courts ruled that the practice of extreme gerrymandering is unconstitutional. The same could be ruled for a party in power advantaging themselves though "ballot harvesting". It accomplishes the same goal, which is giving one party unfair advantage over the other party, thereby disenfranchising those voters. Yeah, fair voting systems is hard. But c'mon. Let's be even in our comparisons. If you rail against Republicans gerrymandering (notwithstanding the fact that Democrats do it too) then call out Democrats for what they do. Democrat politicians are no more moral or upstanding than Republicans. They're all fighting for the power of the stick. They all have their favorite ways to subvert voting systems to give them electoral advantages. Call them all out or call none of them out. But don't pretend one is any less worthy of calling out than the other.
Here's one for you. Republicans/conservatives tend to prefer voting in person at the polls. Democrats tend not to like to bother with that. They'll protest. They'll march. They'll riot. But unless you deliver a ballot right to their ***damn door, it's, "what? go vote? I ain't got time for that what with all the revolutioning I have to do at night."
So yeah. That's a bit of stereotyping, sure. But stereotypes are what they are because tendencies are what they are. This is why, notwithstanding the inherently more exploitable vote-by-mail, Republicans are against vote by mail because it does favor democrats. It's how you get lazy young democrats to vote. You stick it right in front of their face and have a community organizer fill it out for them.