It's a strange world where certain people side with crazed radical terrorists and vilify the civized democracy they attacked, blaming Israel for the suffering and death brought on by an extremist terrorist jihad.
I think the issues that people have with the situation are multi-faceted. Some are shallow, but others have merit.
There are some people who take a very superficial "Israel is aligned with the western colonizers, so no matter what happens, they're the bad guy"
...but that's not representative of all of the objections.
Speaking personally, my objections are:
1) Disproportionality of the response - I was initially supportive of Israel's response in the weeks immediately following the attack, and didn't have any expectation of perfect proportionality, as that would be incredibly naive for people to think that's how war works.
However, when you have an attack that took 1200 lives, once the response reaches 50,000 Palestinians dead and 60% of civilian infrastructure levelled, it's gone well past the point of (figurative and literal) "overkill".
If someone breaks into my car, and I respond by lighting all their cars on fire, burning down their house, their neighbor's houses, and shooting their dog, that goes well beyond "understandable retaliatory vengeance"
2) Netanyahu, more and more with each passing month, has made it clear that this seems to be less about avenging the events of Oct 7 at this point, and becoming more and more about territorial ambitions.
3) They're doing it with our money. Even if Israel was constrained in their response, and using precision, restraint, and avoid civilian casualties as much as humanly possible, that still doesn't explain why we're feeding billions of dollars into a foreign government that has a balanced budget.
If I'm dealing with 3 maxxed out credit cards, and you're sitting flush, even if I agreed 100% with what you were doing, it's unreasonable for you to ask me for the money to do it if your financial situation is better than mine.