Do you want Jesus to give you an easy short-cut to heaven? Who wouldn't! But the path of holiness is a difficult inner journey, not an external guarantee like: If I go to Mass every Sunday, I'm going to stay out of hell. If I serve on various committees at church, I'm winning God's favor. If I fast for at least one hour before Mass, I'm like the folks that Jesus was talking about in today's Gospel reading, because no food is defiling the Eucharist that I consume.
Hey wait a minute! I don't want to be like them!
The kingdom of heaven is not a "future" we hope to attain. God's kingdom is already at hand, here and now. If we accept the fact that Jesus died to heal us from our separation from God -- a separation caused by our sins -- then we live in his kingdom now. Heaven on earth is full of crosses and temptation, but it's still divine. We already belong to God.
Heaven as the after-earth-life is, simply put, the future perfection of the life that we have now. No more crosses, no more temptations, no more impurities in our relationship with God (thanks to purgatory purging out all remaining imperfections). Heaven after death is a continuation of what began on earth.
The path of heaven on earth is a journey of holiness, and our path is defiled by our unholy deeds. We cannot blame the path if we stray from it. Nor can we depend on our path-making tools to carry us to heaven.
Perfect attendance at Mass is only a tool that helps us smooth the road, but if we are not becoming the Eucharist that we consume, and if the true presence of Christ is not coming out from our hearts the rest of the week, what's the point of going to Mass? Staying away from church is no more sinful than going to church and returning home unchanged.
Serving on parish committees is the rock and tar that we use to pave the road, but what happens when someone picks up one of those rocks and hits us in the head with it? If what then comes out from us is evil thoughts, malice, blasphemy, arrogance, or folly, we've been lost on a short-cut that sends us in circles; we haven't been building the path that leads straight to heaven. We've not been following Jesus. Maybe there's a holy card of Jesus tacked to a sign on the road ahead of us, but that's not Jesus.
We dare not blame anyone but ourselves for our unholiness. We are not defiled by the evil-doings of others. When someone treats us unlovingly with evil thoughts, theft, adultery, greed, malice, deceit, envy, arrogance, or folly, these are only externals. How we react to them shows us what's in our hearts: holiness or defilement, Jesus or a plastic statue of him, heaven or worldliness.