This will run a little parallel to your question but I hope provide an answer as to why Yugoslavia and Mexico got on.

You mention in your question about diplomatic ties but the ties between Yugoslavia and Mexico actually ran a lot deeper than that when it came to culture. Soviet cinema, etc was banned due to Tito and the USSR often being on poor terms and US/western was similarly prohibited as subversive. What wasn’t disallowed was Mexican cultural output - Mexican cinema at the time glorified its own revolution and Tito saw many links between that historical event and what was going on in Yugoslavia at the time - specifically the narrative of the common man overthrowing the elites. This was huge in Yugoslavia itself - many mariachi bands came out of the region in the 1950s and 60s because nothing else was allowed to be imported and it’s only come the early 60s that you start to see western music getting imported into Yugoslavia. This was popular at the highest level - singer Nikola Karovic recorded the Malagueña Salerosa with none other than Tito himself playing on piano. The cultural influence of Mexico on Yugoslavia in that era is hard to understate - the film Un Dia de Vida launched in Yugoslavia in 1952 and was a staple in cinemas throughout the nation for the following two decades.

Once “western” music started to come into the country - initially being brought back by footballers touring Europe (not least Dinamo Zagreb legend Slaven Zambata who bought western records specifically to give to Radio Zagreb to form their playlist) - Yu-Mex died a death. By the 80s, the stars of the 60s were left playing the pub circuit while some of the rhythms of their music had been pulled into other genres, not least in Dalmatia.

So Mexico exported a lot to Yugoslavia culturally and, while that may not directly answer your question, I hope it provides an understanding of the cultural ties as to why it’s not that bizarre that Mexico would put up a statue of a seemingly unrelated leader.