They were looking at a protest with very right-wing, reactionary components and a significant US backing, and before the bulk of the casualties occurred the protestors burned alive a PLA soldier. You can't have the tanks rolling in on every protest, but you certainly don't just lay down and accept a right wing coup attempt.

Let's say nobody died

Some students and soldiers did die though, and the government has not denied this. Of note here, if we are concerned about the scale of the bloodshed, is that many students vacated from the situation peacefully. Many who were remained in the square were certainly influenced by the most hardline leaders such as Chai Ling (working closely with the CIA), who all but admitted she wanted the students to die for her goal. She said, in her own words:

The students keep asking, “What should we do next? What can we accomplish?” I feel so sad, because how can I tell them that what we are actually hoping for is bloodshed, for the moment when the government has no choice but to brazenly butcher the people. Only when the Square is awash with blood will the people of China open their eyes. Only then will they really be united. But how can I explain any of this to my fellow students?

(Are you going to stay in the Square yourself?)

No, I won’t. Because my situation is different. My name is on the government’s hit list. I’m not going to let myself be destroyed by this government. I want to live.

So, the tragedy of the June 4th incident was not a cold blooded massacre of dissidents, where the military rolled in the tanks and murdered thousands of people. There was chaotic skirmishing between soldiers and a congregation of students and workers with largely nonuniform political demands, with the more animated among them seeking to overthrow the government. Several hundred people died as a result.

The distortion of truth around this event is genuinely alarming. It's clearly a story that defines of a lot of westerners' views on the entire country of China, when even their understanding of this single event is so far from reality it is practically pure fabrication. Below I'm quoting this essay on the topic: https://redsails.org/another-view-of-tiananmen

As with the leaders of the Tiananmen Student movement, we could go on. Any serious effort at contextualizing the tragedy of Tiananmen would inevitably render the simple truth that what has made Tiananmen an exceptional event in modern history had nothing to do with its brutality, or that it happened in a period that we have retroactively imagined as peaceful, or the virtue of the fallen students. What keeps it a yearly staple of our media diets is simply its sheer utility in destroying international proletarian solidarity with China, and so safeguarding the stability of bourgeois rule in the West.

Could bloodshed have been avoided? Had there not been that ever-helpful US meddling... we can discuss that as well as other hypotheticals ad infinitum. What happened in reality was a tragedy and cannot be changed. It also cannot, with any amount of intellectual honesty, be used to completely discredit and dismiss the Chinese socialist project wholesale the way it has always been used.