Hatred stirs up strife,
But love covers all sins.
Proverbs 10:12 (NKJV).
Love is an idea that has a lot of connotations, being used in a wide range of contexts. It's associated with feelings, with circumstances, with preferences, with motivations, it shows up pretty much everywhere.
Here, love is used in a contrast with hate in how people behave, where love can overcome problems, and hatred will cause them. Seems easy, right?
The question then is "why doesn't everybody love everybody else?"
Simply, the reason is because it costs to love, and finite beings have limited resources.
Humans are affected by the consequences of sin, and there are problems that we do not have the capacity to just ignore. Because of this relationship, where we are not independent from sin, humans cannot really love one another unconditionally. It's simply beyond our capacity, by definition, because we are not omnipotent.
We can try, and learn to love more, but we'll never perfect it, which is why Solomon spends so much time trying to warn against the follies of sin. People who love us will seek means for reconciliation, even at a cost to themselves, but for everyone else our sin creates a debt that must be repaid by our efforts, not by guilt-tripping those we have sinned against to "just love us".
You see, modern philosophies seek to try and invert the dynamic of the debt of sin, in that when someone wrongs you, it's your job to "be the bigger person" and absorb the damage caused from sinful behavior, while those who have sinned against you get off with little more than a stern warning.
People did this with God and with other people, which is why the universal salvation heresies became so popular. All of the sudden, it wasn't about how badly we have sinned and fallen short, but about how much God loves us, and how God would absolve all the consequences of our sin because of that love.
The truth is that God's love does not exist in a vacuum, and in fixating on God's love, God's justice and wrath were ignored, to the eternal peril of many. Sin is a violation of what God desires for our existence, it's a rebellion against God's order of things, and when we sin we bear the responsibility for the damage we cause, to correct what we have done wrong.
Jesus Christ did not eliminate that cost, merely repaid the debt conditionally, where we still have to accept his sacrifice on our behalf, to place our faith in him and not on anything else. This is easier said than done, because just saying it, or thinking it, isn't doing it.
While our actions are not what saves us, they do reflect that we have been saved and by demonstrating that we have genuinely shifted our priorities to reflect understanding truth and not continuing to entertain hollow fictions of our own designs. Even so, when tapped into the love that God has for us, and that can then be shared with others, we are still limited on our capacity. We are still damaged by sin. We are still limited in our ability to resolve the consequences of sin, and so even on the "other side" of salvation, we are never able to love unconditionally the way that God does.
Look, for example, at the New Testament recommendations relating to behavior of "brothers" in the church living in unrepentant sin. We are not to maintain intimacy with them, we are not to try and "cover" their sin with our (or God's) love, but we are instead to protect the body from the consequences of such unabashed sinful behavior and no longer have fellowship with them.
If one commits murder, does "love" bring the person murdered back to life?
If one commits adultery, does "love" undo the adulterous affair?
If one is drunk, does "love" bring down blood-alcohol content?
Love then does not eliminate sin, but simply provides a reason, a justification, as to why grace or mercy could be shown at all.
Love is cited as powerful, and while true, we have to be honest about our own limitations and not be deceived by lofty rhetoric which leads us down a path of destruction. Humans are finite creatures, our love is always limited, even when we are reconciled to God, and so despite our best intentions we will find we have inspired only hatred and conflict when our "love" has run out and there is still a debt to pay for our sins.
People do not hate those who could not ever pay their debts, but they would especially hate one who claimed they would to then back out at the last minute due to foolishness.