I have some personal experience with this, given my own connections with present day Ecuador, where the current government is pretty much exactly like Allende's and following the same policies that Allende ran on and briefly started implementing after being elected president, including land confiscations of any farms over 80 hectares in size (which is not really a very big, oligarch-sized farm at all).

The subsequent, 21st century success in Ecuador, Bolivia, and Venezuela of equally radical, socialist policy objectives to confiscate property, eliminate freedom of the press, and through constitutional changes cement institutions systems in place through which which ruling socialist parties retain extreme advantages in winning re-elections through control of courts, legislatures, election commissions, and even the media, were also all publicly part of Allende's vision for Chile decades earlier.

The fact that such policy objectives through non-violent, majoritarian politics were all eventually successfully implemented in Venezuela, Bolivia, and Ecuador a few decades later, explicitly following Allende's model and learning from his mistakes, shows that the threat perceived by people of moderate or higher wealth in Chile at the  time was perfectly rational.

Without excusing the horrendous, criminal mistake that Pinochet turned out to be, if you were at least moderately wealthy at the time in Chile, you had a very good reason to be asking the US Embassy for help in getting rid of the mobs of goons with the power of the state who were taking away your life's savings and work, as happened to many people in Chile after Allende was elected.

Likewise, for those of us who have farms of that size in Ecuador, Bolivia, or Venezuela today, it makes perfect sense, moral or not, to want overthrow the "21st Century Socialism" governments by any means necessary as our property gets confiscated and our advocates are jailed for speaking out against government corruption and things like that. Or, for those of us living in the US today, we have an equally rational reason, regardless of morality or legitimacy, to want to overthrow Trump's fascist administration before anything worse happens. Many people in Chile felt the same back then about Allende, and with perfectly good reason.