if all you did was quick glance it, then you have no argument
Heresies were warned of appearing by Paul himself, is it a surprise that we find them with these sinful men?
You will learn from heretics from what they criticize - they are criticizing the original church.....and thus you will see the original church believed what the Catholic Church still says...the Eucharist IS Jesus Christ.....
No, it is not, and the tendency to "think of men above that which is written," (1Cor. 4:6) in elevating tradition (even to falsely claiming this "faith which has been believed everywhere, always, by all" - Vincent of Lérins, c. 434), resulted in perpetuation of errors under the premise of perpetual magisterial infallibility.
Which is itself a product of itself, for Rome has presumed to infallibly declare she is and will be perpetually infallible whenever she speaks in accordance with her infallibly defined (scope and subject-based) formula, which renders her declaration that she is infallible, to be infallible, as well as all else she accordingly declares.
However, as with "Trail of Blood" and other like Polemics, Cloud, whom i have some respect for, presents such men as Vigilantius, Jovinian, and Helvidius and the "Bible-believing Donatists" as dissenters without stating that such typically men held other Catholic errors or believed in things both sides hold as heretical.
To which can be added Montanists, Novatianists, Donatists, Paulicians, Albigensians, Catharists, Waldenses.
The church has and will overcome the gates of Hell, but the church is the body of Christ as it alone wholly consists 100% of believers, unlike its visible bodies in which they, as well as tares, express what they believe.
And just as God often provided and preserved faith by raising up men from without the seat of power, as well as by wise overseers, and which is how the church began, then so has faith and the church been preserved.