I am not ashamed to say that I don't respect the belief (if it exists) that following the pope on Twitter will reduce the follower's time in purgatory. This is partly because I don't believe in purgatory though I respect anyone else's right to believe in it. But it's also because I think it's an utterly ridiculous thing (the shortening of time in purgatory by doing something on Twitter) to believe though, once again, I fully respect anyone else's right to believe it.
How about those who always complain when I mock a belief (a belief, note, not a person; the OP is not mocking anyone, only an abstract thing; no-one is damaged (nor their beliefs) by its being mocked)... where was I?... oh yes... how about those people respecting my right to mock what I think is silly, and I'll carry on respecting their right to believe anything they choose, even if I think it's silly and say so.
Now, mock my belief that this purgatory offer is silly. Mock it. Don't complain about it hurting anyone or the fact that I voice it.
Finally, the point that is achieved (since somebody asked) is the declaration that it's allright to mock ideas, religious or otherwise, that one thinks are ridiculous. I mock scientific ideas that I think are ridiculous too. Religious ideas are not exempt.