These states of mind are not always easy to maintain. They are certainly not a sign of weakness, but on the contrary require great courage. This is especially true now that the world seems to be drifting into a period of lawlessness and warfare. And to have any value compassion and loving-kiondness must be perfectly univeral. Anything less is to cut ourselves off from some aspect of the whole.
Universal love is the gateway to wisdom, anything less is merely mundane particularism.
The Buddha set a high standard for this. He said that if bandits seize you, tie you up and saw off your arms and legs with a two-handled saw, should any thought of animosity arise in your consciousness, then you are not following his teaching. But the first and for many the most difficult challenge is to arouse genuinine loving-kindness for oneself. If you do not truly love yourself, if you do not really have compassion for your own failings, then you can never begin to have it for others in any meaningful way. And, conversely, if you really do have genuine loving-kindness for your own being, then you will not be able to stop there.