Yes, the murder of Litvinenko is considered state terrorism by those who can afford to say so. Its not considered random at all. They very publicly killed someone who was an outspoken opponent of theirs. KGB has a long history of both state terrorism and state-sponsored terrorism.

> THE senior British official was unequivocal. The murder of the former KGB man Alexander Litvinenko was "undeniably state-sponsored terrorism on Moscow's part. That is the view at the highest levels of the British government".

http://www.thesundaytimes.co.uk/sto/news/world_news/article6...

You might think that some forms of terrorism are worse than others, but that doesn't mean that those are the only forms of terrorism.