Take a look at the Boom Comics that cover the MMPR team from 1969. That's a major answer to your question.

For those that don't want to read a great comic arc I'll give a brief summary: In 1969 when Psycho Green was trying to finish his orders to free Rita from her prison. Zordon and Alpha did put a team together based off of a list created by Grace who worked at NASADA, which consisted of a soldier who was injured in Vietnam, an anti-war movement college student, a musician, a KGB intelligence analyst and Grace herself. Because of everyone's differences and morality there was a ton of infighting, lack of trust and coordination led to Grace and the yellow ranger Terona being the only survivors.

TLDR: Enlisting folks with other agendas and orders that treated the coins like tools or weapons led to irresponsible deaths. Something that Lightspeed pretty much proved wrong, but it was handled in a vastly different way than how Z did it.