In it's context in the NRSVCE (including section title):
4 Now the Spirit expressly says that in later times some will renounce the faith by paying attention to deceitful spirits and teachings of demons, 2 through the hypocrisy of liars whose consciences are seared with a hot iron. 3 They forbid marriage and demand abstinence from foods, which God created to be received with thanksgiving by those who believe and know the truth. 4 For everything created by God is good, and nothing is to be rejected, provided it is received with thanksgiving; 5 for it is sanctified by God’s word and by prayer. (1 Timothy 4:1-5 NRSVCE, emphasis added)
This passage appears to list forbidding marriage and demanding abstinence from foods as examples of 'teachings of demons'.
It seems that to enter the priesthood in the Latin rite either a promise (for diocesan priests) or a vow (for religious priests) of celibacy is required. The best argument I've seen so far on this issue, argues that this isn't a 'requirement' but only something entered into voluntarily. But on the surface, this argument seems somewhat at odds with language used in some of the sections of the ordination ceremony of the Latin rite subdiaconate:
You ought anxiously to consider again and again what sort of a burden this is which you are taking upon you of your own accord. Up to this you are free. You may still, if you choose, turn to the aims and desires of the world (licet vobis pro artitrio ad caecularia vota transire). But if you receive this order (of the subdiaconate) it will no longer be lawful to turn back from your purpose. You will be required to continue in the service of God, and with His assistance to observe chastity and to be bound for ever in the ministrations of the Altar, to serve who is to reign. (Source, emphasis added)*
Even if the initial decision was voluntary, the process seems to admit no possibility for a later change. A priest (in the Latin rite) is certainly forbidden from resiling from an earlier intention to remain celibate and to instead pursue marriage.
In regard to 'demanding abstinence from foods', I note that there has been a change since Vatican II, but we still have:
On Ash Wednesday and all of the Fridays of Lent, Catholics over the age of 14 are required to abstain from meat and from foods made with meat. (Source, emphasis added)
Now that doesn't sound particularly voluntary does it?
So what is the Catholic understanding of this verse and why isn't it referring to their practices in these areas?
edit: *I accept Matt Gutting's assurance that the order of the sub-diaconate has been dissolved and the particular text quoted is now only of historical interest and not necessarily a corresponding match to the instructions currently given to modern candidates for the Catholic priesthood. While I'm not sure that this has a significant effect on the underlying issue my question stems from (I'm not aware of a substantial change in the character of, or the requirements for the priesthood post-Vatican II), I'm certainly willing to update this reference to current intructions (or the recommended promissory/avowed responses) if someone is kind enough to provide the text for them.