They probably think it is OK. Spiritism was very popular in the mid to late 1800’s and the Church issued various documents condemning the practice. For example from New Advent:
As Spiritism has been closely allied with the practices of “animal magnetism” and hypnotism, these several classes of phenomena have also been treated under the same general head in the discussions of theologians and in the decisions of ecclesiastical authority. The Congregation of the Inquisition, 25 June, 1840, decreed:
Where all error, sorcery, and invocation of the demon, implicit or explicit, is excluded, the mere use of physical means which are otherwise lawful, is not morally forbidden, provided it does not aim at unlawful or evil results. But the application of purely physical principles and means to things or effects that are really supernatural, in order to explain these on physical grounds, is nothing else than unlawful and heretical deception.
This decision was reiterated on 28 July, 1847, and a further decree was issued on 30 July, 1856, which, after mentioning discourses about religion, evocation of departed spirits and “other superstitious practices” of Spiritism, exhorts the bishops to put forth every effort for the suppression of these abuses “in order that the flock of the Lord may be protected against the enemy, the deposit of faith safeguarded, and the faithful preserved from moral corruption”. The Second Plenary Council of Baltimore (1866), while making due allowance for fraudulent practice in Spiritism, declares that some at least of the manifestations are to be ascribed to Satanic intervention, and warns the faithful against lending any support to Spiritism or even, out of curiosity, attending séances (Decreta, nn. 33-41). The council points out, in particular, the anti-Christian character of Spiritistic teachings concerning religion, and characterizes them as an attempt to revive paganism and magic. A decree of the Holy Office, 30 March, 1898, condemns Spiritistic practices, even though intercourse with the demon be excluded and communication sought with good spirits only. In all these documents the distinction is clearly drawn between legitimate scientific investigation and superstitious abuses. What the Church condemns in Spiritism is superstition with its evil consequences for religion and morality.
From the current Catechism of the Catholic Church paragraph 2117
2117 All practices of magic or sorcery, by which one attempts to tame occult powers, so as to place them at one’s service and have a supernatural power over others - even if this were for the sake of restoring their health - are gravely contrary to the virtue of religion. These practices are even more to be condemned when accompanied by the intention of harming someone, or when they have recourse to the intervention of demons. Wearing charms is also reprehensible. Spiritism often implies divination or magical practices; the Church for her part warns the faithful against it. Recourse to so-called traditional cures does not justify either the invocation of evil powers or the exploitation of another’s credulity.
So at least from what I have been able to determine the Church does not support the practice and in fact advises against being affiliated with it.
