Well, the big one is that it's a joint effort as a society to not continually strengthen bacteria by selecting for strains that are resistant to these antimicrobials.
There have been a small number of laboratory studies that imply it might be possible with triclosan, but they used extremely low levels of triclosan, and real world studies have basically shown the opposite.
http://ec.europa.eu/health/scientific_committees/consumer_sa... Page 30
"Furthermore, in most in vitro studies, resistance to triclosan has been measured as an increase in MIC. As mentioned in section 6.2 above, the measurement of resistance based on MIC only, might have little bearing on bacterial survival to concentrations found in situ."
"Ledder et al. (2006) investigated acquired high-level triclosan resistance in a number of distinct environmental isolates and reported that a relatively small number of strains showed a decrease in triclosan susceptibility (E. coli, Klebsiella oxytoca, Aranicola proteolyticus and S. maltophilia) while the susceptibility of the remaining 35 species remained unchanged. They concluded that repeated exposures to triclosan did not systematically produce high-level triclosan resistance in all bacteria. Furthermore, among the strains with decreased susceptibility, there was no change in antibiotic susceptibility or susceptibility to other biocides. Similarly, another study by the same group on repeated exposure of dental bacteria to triclosan resulted in the same conclusions"
"Cole et al. (2003) collected 1238 isolates from the homes of users and non-users of antibacterial product and were unable to demonstrate any cross-resistance to antibiotic and antibacterial agents in target bacteria. In addition, this study showed an increased prevalence of potential pathogens in the homes of non-users of antibacterial products. "
"With our current state of knowledge, it is generally accepted that antibiotic resistance in clinical isolates is not necessarily associated with resistance to biocides. "
"urthermore, the antibiotic susceptibility profile of the oral streptococci investigated did not change following the use of triclosan containing toothpaste. Aiello et al. (2004) did not find any statistical significance between elevated triclosan MICs and antibiotic susceptibility in bacterial isolates taken from the hands of individuals using antibacterial cleaning and hygiene products for a 1-year period."
"The authors did not observe any increase in triclosan MIC in these bacteria"
As far as I've read from this though, it doesn't apply to the use of actual antibiotics, which do cause strain resistance. That is the issue that I am definitely in support of, and it seems I wrongly correlated anti-bacterial soaps in that issue as a fact when it does not appear to be so.