I think it's a different kind of "Christ" they get with the ritual versus what they get when they are baptized.
Scripture quite clearly says that we are filled with the Holy Spirit, He is within us as the "earnest" (guarantee) of our inheritance, will never leave us or forsake us and confirms that we are His because we have the Spirit of God within us, when we receive Jesus Christ by faith, believing and trusting in His sacrifice for us. We have the assurance that we belong to God and have been adopted into His family by His grace through faith. When we partake with other believers in the ordinance of the Lord's Supper, we are doing so as a remembrance of Him - as He said we should do - and as an outward confirmation that we have inwardly received the participation of His body and blood and have placed our faith in Him to save us and as a testimony of the one loaf all believers are part of: "Since there is one bread, we who are many are one body; for we all partake of the one bread.." (I Cor. 10:17)
In Catholicism, the Lord's Supper/Eucharist is received ONLY after a full confession is done, penance performed and a "state of grace" is achieved by eating the body, blood, soul and divinity of Christ as a propitiatory sacrifice for those sins we just got done confessing. So, the Eucharist is part of the finishing touch, so to speak, of placing one in a state of grace so that heaven is attainable - at least as long as we remain sin-free. When we sin, the cycle begins anew. I really don't think Catholics view the presence of the Holy Spirit within each believer as equal to having Christ within them - which they get by going to Communion and which only lasts as long as until the next time they sin.
Historically, the Roman Catholic Church did not always view the Eucharist as expiatory. They did not see it as a reenactment of the sacrifice of Christ on the cross that made participation critical to a person's very salvation. That doctrine developed over many centuries and just as we can see the doctrine of justification by faith change to faith AND works, so, too, did this sacrament change to be THE most essential part of the worship service and life of the Catholic.
Now, I'm sure there will quickly come the castigations, sarcasms and accusations that I wasn't properly catechized and that I didn't say it "right", that I don't know what I am talking about, and so forth, but this IS the way most Catholics view this part of their faith. It's why they can patronize and condescend to us non-Catholic Christians and say they feel sorry for us because we miss out on getting "God" in us like they do. In reality, I'd much rather have Christ within me 24/7/365 than once a week (if I'm a good girl) with no assurance of salvation. We can KNOW we HAVE eternal life and this is because we have believed in Christ and God's grace imputes HIS righteousness to our account through faith. We are saved NOT by the righteous things we do - like receive the Eucharist or getting baptized - but by grace and mercy given to us through faith. I think this is the far more wonderful truth!
And yet, when they read the FACTS, posted from their catechism*, out LOUD; their ears must be plugged up.
* reply #46