Iran's mass murder after the protests was not ignored. We had a mass protest in my city. I'm not sure if you can call it genocide because it's their own people, the same race and identity. It's certainly mass murder and terrible but not an attempt to change the population racial makeup. Thus the label genocide doesn't qualify, but yes the actions are morally equally bad. Just a different label.
The reason there's less attention is twofold:
First of all our countries support Israel so we are complicit. That calls for more protest among us who don't agree because there's actually something we can change. Iran is not going give a crap when they see people marching in protest in Europe.
Another thing is that Israel has no business being in Gaza in the first place. Iran's government unfortunately does have a legitimate claim to governance in Iran.
I'm not against Jews at all but I am against my country supporting genocide.
Also I don't think one country unilaterally bombing a place they have nothing to do with is the answer to any problem.