I suspect that Henry Robinson was a bit of a radical. We already have the evidence of his indictment in 1843. Here is some further evidence, although it is indirect.
In March 1863 Edward, Prince of Wales (the future Edward VII) married Princess Alexandra of Denmark. The Caledonian Mercury of March 16th 1863
was a Special Marriage Edition and it includes very detailed descriptions of illuminations and street decorations in Edinburgh. Here we find:
LEITH STREET AND GREENSIDE
...
Mr Henry Robinson, bookseller, exhibited a large illuminated crown, and two fine engravings, the one representing the declaration of American independence, and the other portraits of the various American Presidents, from General Washington to Lincoln. The shop was gaily decorated with British, Danish, and American flags.
…
Looking over the rest of the page I see mentions of portraits and transparencies of the couple (and of Queen Victoria), lots of Prince of Wales' feathers, hearts, Chinese lanterns, illuminations based upon gas jets, royal mottoes, coats of arms, flags etc. etc. But no other mention of America. Perhaps he was signalling his republicanism?