Because of The Internet, the demand for a common language is getting higher. And it seems better to have consensus of what language to use.
Here is a letter he wrote about the motivation of his creating Esperanto.
"The place where I was born and spent my childhood gave direction to all my future struggles. In Białystok the inhabitants were divided into four distinct elements: Russians, Poles, Germans and Jews; each of these spoke their own language and looked on all the others as enemies. In such a town a sensitive nature feels more acutely than elsewhere the misery caused by language division and sees at every step that the diversity of languages is the first, or at least the most influential, basis for the separation of the human family into groups of enemies. I was brought up as an idealist; I was taught that all people were brothers, while outside in the street at every step I felt that there were no people, only Russians, Poles, Germans, Jews and so on. This was always a great torment to my infant mind, although many people may smile at such an 'anguish for the world' in a child. Since at that time I thought that 'grown-ups' were omnipotent, so I often said to myself that when I grew up I would certainly destroy this evil."
— L. L. Zamenhof, in a letter to Nikolai Borovko, ca. 1895