Hogg tangled with Harry Arter with just over an hour gone, losing composure in an incident which saw him nudge the Republic of Ireland international with his head before shoving him to the ground.
Referee Michael Oliver did not get a good look in real time but an eagle-eyed assistant saw enough for him to reach for the cards - yellow for Arter and red for the simmering Hogg.
The tenor of a match between two sides who did little to dispel gloomy predictions about their Premier League fates shifted immediately.
Huddersfield's forward momentum, which had admittedly drawn only one save of note from Neil Etheridge, was halted in an instant and a previously reticent Cardiff belatedly discovered some ambition.
"It was a game changer wasn't it," said Wagner after banking a first point of the campaign.
"The incident with the red card was soft but, to make it totally clear, Hoggy has to solve the situation better. It was two aggressive players in this moment.
"One was much more clever than the other and unfortunately the clever one was not my player."
If that constituted a relatively mild reproach for Hogg's intemperate reaction, Wagner was clear about the impact on his game plan.
"Until this moment we controlled the game, we were the team which wanted to play forward and create opportunities," he said.
"We always say when we keep the tempo high you get chances in the last 10-15 minutes. I can say now it was a good point for us, but if we could play the last half hour like we played the first hour I would be very disappointed with a point."
Cardiff have problems of their own after drawing three consecutive blanks on their return to the top tier.
Tuesday's Carabao Cup clash with Norwich may see the drought end but games against Arsenal, Chelsea and Manchester City are next up in an unforgiving September schedule.
"We're in the Premier League and that's how it is, at least we've got three easy games coming up to get a goal on the board," said Warnock.
"We'll score eventually," he added with a wry smile.
"We should have won and I'm disappointed we didn't. I was pleased with the shape but we didn't have enough in the final third again."
Cardiff will wait for news on Nathaniel Mendez-Laing's fitness following his match-ending first-half collision with goalkeeper Ben Hamer.
"We won't know for a few days, we can't even scan it so it will be the middle of next week," said Warnock.
"He was brave and he got to the ball before their keeper...it makes you wonder what you should do in those situations."
Hamer also left the field after trying to continue, allowing Jonas Lossl to make his first appearance from the season from the bench.
Lossl will start in the cup against Stoke on Tuesday, where he will get the chance to reclaim number one status.