Why? Why is Calvinism so feared?

[panta dokimazete]

Because if He did not love me enough to overwhelm my will...

Maybe I'm nitpicking but "overwhelm" has connotations like "bully" that are foreign to what Scripture tells us God does.
Wouldn't "free my will" be better?

Anybody who is unsaved has a will that is free to choose only evil some of the time and never God or his ways. It is the one who God regenerates who can choose to offer himself or herself to God and his or her members as instruments of righteousness for sin shall not be [their] master for [they, and they alone] are not under law but under grace. Cf. Rom 6:1-14.

2 Corinthians 5

13For if we are beside ourselves, it is for God; if we are in our right mind, it is for you. 14For the love of Christ controls us, because we have concluded this: that one has died for all, therefore all have died; 15and he died for all, that those who live might no longer live for themselves but for him who for their sake died and was raised.

So when I say "overwhelm" it is in that sense. That my steps are ordered to live for Him and not for myself, despite my worst efforts.

Romans 8:29
For those whom he foreknew he also predestined to be conformed to the image of his Son, in order that he might be the firstborn among many brothers.