I've read the Wikipedia page and though he's a despicable person I see no reason why he should be excommunicated. There were more extreme right persons in the hard-core Catholic niche.

Latae sententiae excommunication happens automatically when a person takes certain actions, without any trial or proclamation being needed. Examples of latae sententiae offenses include apostasy, stealing a communion wafer, physically attacking the Pope, and procuring a completed abortion. Thus, if Fuentes were to pay for someone to get an abortion, he would thereby become excommunicated without anyone else necessarily knowing about it.

https://en.wikipedia.org/wiki/Latae_sententiae

Validity of a specific canonizations constitutes De fide ecclesiastica definita (stated with infalibility by Magisterium), denying it publicly and with audacity causes the Latae sententiae excommunication to happen on the grounds of heresy, all it would take is for Fuentes to be adamant about specific saint being canonized wrongfully.

https://www.vatican.va/roman_curia/congregations/cfaith/documents/rc_con_cfaith_doc_1998_professio-fidei_en.html
"With regard to those truths connected to revelation by historical necessity and which are to be held definitively, but are not able to be declared as divinely revealed, the following examples can be given: the legitimacy of the election of the Supreme Pontiff or of the celebration of an ecumenical council, the canonizations of saints (dogmatic facts)"

Does the Catholic church still excommunicate people?

Yes. In addition to automatic excommunications (latae sententiae) there are also recent formal excommunications.

https://en.wikipedia.org/wiki/List_of_people_excommunicated_by_the_Catholic_Church#21st_century