The last episode of Shark Tank had 6 million viewers . If we pick $1/thousand impressions as a reasonable advertising cost, you'd have to spend $600K for 6 million impressions. It's difficult to overstate how good this deal is. That's what you'd be looking at paying for a Google ad that is displayed for a few seconds while a user searches or reads a page (not even looking at your ad). On Shark Tank you're holding people's direct attention for 5-15min.
For you to start losing money, ABC would need to take > 600K out of your business. At 5% equity, that equates to $12 million in distributable net profits. Let's say the life-time of your business is 10 years - that's $1.2 million net profit distributed to shareholders/year. To redistribute $1.2 million/year you're looking at (one imagines) at least 4 times that in net profit before taxes, i.e. $4.8 million. If your net profit margin is an optimistic and very healthy 30% that's $16 million revenue/year.
To be generating $16m revenue/year makes you a pretty successful business and the chances are if you got to that point it's because you were on Shark Tank. Very few people grow a business to that size without spending substantially more than 600K on advertising and investment.
At that point, assuming you still own 65% of the business (you negotiated 30% away to Shark), you're pulling in 780K (65% of $1.2m) per year vs. ABC's 60K/year. And this is a bad deal?
In addition the Sharks know this and have an unfair advantage as investors that would motivate them to make deals. So ABC is also attempting to level the playing field a little bit