I was planning on giving Capital One (NYSE: COF) the benefit of the doubt. In fact, I was even saying that the acquisition of ING's (NYSE: ING) ING Direct unit could work out quite well for Capital One if it was able to use ING Direct's solid deposit base to fund higher-interest loans.

On Monday, I concluded, "Overall, I'd have to give this acquisition a thumbs-up from the perspective of Capital One shareholders."

However, after being pointed to the ING Direct Facebook page, I'm wondering whether I stuck my thumb up prematurely. Based on the comments on the Facebook page, many ING Direct accountholders are not happy about this deal, to put it mildly. Here are just a few of the hundreds of critical comments that show up not only on the announcement of the deal, but also on every subsequent post on the page.

  • "This is no way to treat loyal customers, ING. This stinks!"
  • "Very sad news. Feels like losing a longtime friend."
  • "This change is not good. The only company on this planet worse than Capital One is [Comcast (Nasdaq: CMCSA)]."
  • "I came in this evening guess what's in my mailbox? A mail from Ally Bank guess they knew I would be needing them."
  • "We hate Capital One!!!"
  • "ING is dead to me ..."
  • [In response to a post about the first day of summer and sunscreen:] "You shouldn't be worried about sun screen but not losing customer when ING becomes Capitol One ... I know im leaving!!!"

Please don't hate us!
It gets better. Yesterday, the folks running ING Direct's Facebook page were apparently trying to save face and wrote: "We hear you, Savers. The plan is ING DIRECT + the best of Capital One = more ways to help you save." That was basically the equivalent of knocking the hornets' nest off the tree and kicking it repeatedly until every last hornet was sufficiently enraged.

The responses?

  • "Goodbye, ING Direct. Can't in good conscience do business with Capital One."
  • "There's no way I'm letting Cap One have a dime of my money!"
  • "Peace out Crap One!"
  • "I will join my local credit union ASAP"
  • "The best of Capital One? That's like saying the best parts of colon cancer."

My bad?
In Capital One's slide deck for the deal, its bullet points pitching the deal's "compelling strategic value" include:

  • "7 million young, high-income, loyal customers"
  • "$80 billion of low cost, stable deposits"

Emphasis mine in both cases.

Granted, hundreds of angry comments on Facebook don't absolutely prove that ING Direct's entire customer base is going to jump ship, but it definitely calls into question whether those loyal customers will stay anywhere near as loyal or those stable deposits remain anywhere near as stable under Capital One.

And if they don't? Well, Capital One may be looking for a towel to wipe the egg off of its face.

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Fool contributor Matt Koppenheffer has no financial interest in any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or Facebook. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.