I would place these claims inaccurate, due to improper representation of the study that the Cracked article itself supplied.
Conclusion: "Five years after completing structured weight-loss programs, the average individual maintained a weight loss of >3 kg and a reduced weight of >3% of initial body weight. After VLEDs or weight loss of ≥20 kg, individuals maintained significantly more weight loss than after HBDs or weight losses of <10 kg."
While the >3 kg, which with a conversion of ~2.2lbs/1kg comes to roughly >6.6lbs does not seem substantial (although it is far from the "rounds to zero" that the Cracked article claims in its header), it is important to note two points from the article. Under "Study Identification," the article states " Follow-up values were assessed at 1, 2, 3, 4, and 5 y." Under "Meta-Analysis," it states that "Weight-loss maintanance(kg)=initial body weight-bodyweight at follow up. As defined by the article, the ">3kg" refers not to the entirety of weight loss throughout the trial, but instead to the weight loss observed at the annual follow-up (overall averaged out). This is further exemplified by this table, which more clearly lays out the parameters of the conclusions of the trial - http://ajcn.nutrition.org/content/74/5/579/T2.expansion.html, and a graph which shows the long-term weight loss maintanance http://ajcn.nutrition.org/content/74/5/579/F1.expansion.html .
Given that they represented this study so greatly, and the other study was not a study focusing on individual trials, but instead on methodology for weight loss and the reasons for its importance, I believe it is fair to say that the other claims made in the article are unsubstantiated.
As for the second question, there is currently a great amount of evidence to indicate that weight loss programs can be successful. When reading these studies, it is important to remember that averages are, ultimately, averages, and due to many modern clinical trials following intent to treat analysis (a method in statistics that retains "bad" or failed results in order to be more statistically true to the data, as well as be more representative of real world situations) the weight loss will likely be higher for those dutifully following the parameters of the trial, which can be demonstrated this through a 2011 study published in the New England Journal of Medicine (http://www.nejm.org/doi/full/10.1056/Nejmoa1108660#t=articleResults)
In this trial, which focused on comparing the effects of two monitored weight loss programs versus a third with no intervention, the following results were found: "At 6 months, the mean (±SE) adjusted change in weight from baseline was −1.4±0.4 kg in the control group, −6.1±0.5 kg in the group receiving remote support only, and −5.8±0.6 kg in the group receiving in-person support. t 24 months, the mean change in weight from baseline was −0.8±0.6 kg in the control group, −4.6±0.7 kg in the group receiving remote support only, and −5.1±0.8 kg in the group receiving in-person support." This is slightly more optimistic, but what is more indicative of the potential benefits are in Table 3. (http://www.nejm.org/doi/full/10.1056/Nejmoa1108660#t=articleResults) . At 6 mo and 24 mo, statistical significance was found for obtaining a BMI <30 when utilizing both support and remote. As the NIH identifies obesity as a BMI equal to or greater than 30, this means that there was a significant effect of monitored, dedicated weight loss therapy on helping individuals overcome obesity in a trial extending for two years. This implies that there is a great deal of optimism in terms of overcoming weight problems, if one is capable of following a more rigid regimen with the aid of an external, motivating source such as those demonstrated in the trial.