Not true. Ejecta has been supporting WebGL for a while now. It was announced in this blog post: http://impactjs.com/blog/2013/05/ejecta-1-3

If you're doing WebGL stuff, I would encourage you to get the current Ejecta dev version from Github, instead of the last release version. There have been a lot of WebGL related bugfixes since: https://github.com/phoboslab/Ejecta