You have some good things going on here. I like your end rhymes, particularly how you mix them up between the first two stanzas and the last two. Going from quatrains to tercets is a move that might seem to be an arbitrary shift, but you validate it by giving the tercets their own unique rhyme scheme. I particularly liked the slant rhymes of do / room, and eat / me.

You can make this poem a lot stronger if you pay more attention to your scansion. While none of your lines fall into flabby, prose rhythms, neither do they lock into the kind of pattern that you create with your rhymes, the type of poetic effect that exists apart from the actual content, but which can serve to buttress that content and enhance its effect.

Your first line scans into perfect iambic pentameter, all the stronger because it requires no awkward stresses on syllables that wouldn't ordinarily take a stress in a normal reading.

"You dont / be-long / in here / .", the preach / er said.

That's the trick with things like meter and rhyme, to hide them inside a natural reading of the words, as though this is how they'd be written any way, and the poetic tricks are just a happy coincidence. Then the next three lines each scan into four perfect feet. This isn't wrong in itself; it's not as though you've violated a rule from the poetry manual. In truth, there are no rules, save the ones you make up yourself, as you did with the combination of quatrains and tercets and their separate rhyme schemes. The catch is, if you create a rule for yourself, you need to follow it, or you lose the internal consistency that gives a poem its strength.

And point / ed his fing / er, as preach / ers do,

To the / old man / in the back / of the room

Then stomped / and shout / ed un-til / he was red

So far, so good. Four lines of elegantly scanned verse, in a pattern unique to the poem, but certainly valid.

Unfortunately, the second stanza makes no attempt to duplicate this scansion scheme. In fact, only the third line falls into four clean metrical feet. The other three lines all have misplaced stresses, too many weak beats clumped together or beats that are missing, to flow elegantly off the tongue.

The last two stanzas likewise have an irregular assortment of weak and stressed beats. The last line in stanza three falls neatly into four metrical feet; the others have the same awkwardly placed beats, or missing beats, that plagued stanza two.

As I said, you haven't violated any rules so much as you have neglected to create any rules for yourself at all. The result comes off as careless, when it could, with a little more attention to the scansion, be a strong bit of verse.

I suspect that you have a natural facility for words, and that ability carries you a good way. You are doing many things right, and perhaps you aren't even aware of all that you are doing right. That's fine. Don't look too closely at it, if it's working. But the specifics of scansion are worth mastering, particularly since the elements are so simple. Once you understand what's at stake, you will naturally edit your output to avoid the kind of near misses that you now have.

If you already know about metrical feet and how they are the natural way that English organizes itself when it "sounds good," then go back to each of your lines and tighten up the rhythms. If you aren't sure what it's all about, there are plenty of resources on this site that could steer you in the right direction. You could do worse than this little essay by yours truly, "Poetic Feet and Meter" . The minimal work that would be required would immeasurably improve the impact of your poem. I hope you'll look into it.