Foma, for me there are just two sides. It is difficult to discuss it here because it is a political discussion which would last at least hours maybe days to discuss it properly. I think the topic is really difficult. Of course it is a tragedy for Russian fans and it is a tragedy for you, and i feel really compassion about it.
On the other hand i think an artist as Mark Knopfler must be very wary what he does and what he does not. And i'm glad that he thinks about it and that he dares to declare himself (regardless whether his decision is right or wrong) Politians always try to misuse the glory of famous persons for their own reputation. I don't have an inside view into the Russian system, i only know some Russians who are living nearby, i like them and i even work together with them. They have all a different view to Russians politics, and so do we.
At the moment there is the military conflict in Ukraine where Russia is involved strongly and where also western countries (Putin thinks the Nato, probably he is right, don't know it) are involved. There is a propaganda war on both sides, so nobody can be sure what is right and what is wrong. So nobody here can make a decision that is based on logic and ratio because everwhere are only lies. So for this tour i can somehow understand that he is not playing in Russia. The situation is complete unclear, although the everydays life in Moscow is as ever.
The other thing is that from the view of many European countries (we are talking here about the majority of the inhabitants and not about all of them, there are also many inhabitants who have another opinion) Putins politics and how he is orientied has worrying signs. And the main question is does the Russian system really guarantee the values of a democracy. Western point is that Putin is loosing these values and is changing the direction, in Russia, however, he is very popular. There were huge (really HUGE) political changes in the last three decades in Russia. At this decisive point it is very important what is going to happen in the Future. Mark made a sign that he is for democracy, for separation of powers, for liberty of speech and freedom of expression. And he criticised that the Russian state didn't care about some of this values. He made clear that he is against Putins politic and he tried to make in that situation a sign. I like that sign, i'm very sad for you, because you are a big enthusiast, and indeed it's sad for a thousand of fans, but he has the right to do so (As you would have the right to boycott his concerts!). I like the Russian mentality here, and there is much understanding, but i think its good to make signs. And unfortunately there is not a clear division between arts and politis. Better he made that sign (even if it could be wrong) than supporting the possible wrong side.