It is unjust because it amplifies the voice of some at the expense of others. For example, a voter in Wyoming carries the same weight as about 4 Californians. The majority shouldn't be subject to the will of the minority. Crazy. There is no tyranny of the majority, but there certainly is a tyranny of the minority. In our time, it is quite literally MAGA. Decidedly minority, but running the show. I felt oppressed and highly resentful when Trump was in office.
The electoral college also suppresses the vote by removing incentive to vote. Pointless to vote for president in Oklahoma or California.
Additionally, there is potential to override the outcome in an entire state as the GOP was and is threatening to do. We shouldn't be so naive as to think that won't happen. Most of the people on this BBS probably want it to happen.