You are absolutely right that Jesus single new commandment was that we are to love one another.

Part of that love is getting everyone the information necessary to achieve eternal life - that means first believing and then obeying because of that belief.
These are the essential things that Jesus Himself requires of us: in His own words (John 3:16-20)

For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life. For God did not send his Son into the world to condemn the world, but to save the world through him. Whoever believes in him is not condemned, but whoever does not believe stands condemned already because they have not believed in the name of God's one and only Son. This is the verdict: Light has come into the world, but people loved darkness instead of light because their deeds were evil. Everyone who does evil hates the light, and will not come into the light for fear that their deeds will be exposed. But whoever lives by the truth comes into the light, so that it may be seen plainly that what they have done has been done in the sight of God.

So, clearly, Jesus tells us that there are deeds that are evil. That would include my own heterosexual desire to mate with half the world's population.

Somebody has to communicate to everyone the things that offend God. Jesus tasked his disciples with the following Great Commission:

,,,go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you.

So obedience is important. This included obeying the above command. So when a disciple of Jesus attempts to teach others to obey all that Jesus commanded them, they go forth and do that, not out of hate, but out of obedience and love.

Not loving someone is not caring enough to endure the ridicule and scorn that comes from those who love the darkness so that we can get them the information that they need to have eternal life.