Your “facts” don’t match the facts.
https://www.kent.edu/may-4-historical-accuracy
Don't pontificate about things you know nothing about.
The answer offered by the Guardsmen is that they fired because they were in fear of their lives. Guardsmen testified before numerous investigating commissions as well as in federal court that they felt the demonstrators were advancing on them in such a way as to pose a serious and immediate threat to the safety of the Guardsmen, and they therefore had to fire in self-defense. Some authors (e.g., Michener, 1971 and Grant and Hill, 1974) agree with this assessment. Much more importantly, federal criminal and civil trials have accepted the position of the Guardsmen. In a 1974 federal criminal trial, District Judge Frank Battisti dismissed the case against eight Guardsmen indicted by a federal grand jury, ruling at mid-trial that the government's case against the Guardsmen was so weak that the defense did not have to present its case. In the much longer and more complex federal civil trial of 1975, a jury voted 9-3 that none of the Guardsmen were legally responsible for the shootings. This decision was appealed, however, and the Sixth Circuit Court of Appeals ruled that a new trial had to be held because of the improper handling of a threat to a jury member.
The legal aftermath of the May 4 shootings ended in January of 1979 with an out-of-court settlement involving a statement signed by 28 defendants(3) as well as a monetary settlement, and the Guardsmen and their supporters view this as a final vindication of their position. The financial settlement provided $675,000 to the wounded students and the parents of the students who had been killed. This money was paid by the State of Ohio rather than by any Guardsmen, and the amount equaled what the State estimated it would cost to go to trial again. Perhaps most importantly, the statement signed by members of the Ohio National Guard was viewed by them to be a declaration of regret, not an apology or an admission of wrongdoing:
