If its about IRS then its related to the United States and if anybody should be targeted, it then means your information provided at some point have been compromised for them to that you have interest in crypto. One reason why one needs to be more careful where you drop your contact details online and where you fill and all sorts of verification processes. I have not been contacted, but I think its just common sense just like the amount of PMs sent on the forum by bots or newbies advertising some forms of ICOs that don't even exist. What you do is just to ignore. No one is making you do such at gun point.