Note:
(a) "言论哗然" because his latest remarks are unexpected. 赖清德 projected an image he is the ONLY major politician in Taiwan -- even within Democratic Progress Party (DPP) -- who openly supports, if not champions, Taiwan independence.
(b)
(i) 赖清德 LAI, Ching-Te (1959- ; 生于台北县万里乡（今新北市万里区）矿工家庭; 建國中學 (1975-1979; it seems he spent 4, not the usual 3, years in high school), 台湾大学复健医学系学士、成功大学学士后医学系、美国哈佛大学公共卫生学院硕士; 曾任医师; 台南市长 2010- )
(ii) The en.wikipedia.org has a page about him under the title "William Lai."
(iii) 羅弘旭, 焦點人物：礦工之子、二歲喪父 苦讀出身的台南新科市長; 賴清德：每場人生戰役都要把自己逼到極限. 今周刊, Dec 1, 2010 http://www.businesstoday.com.tw/ ... 0%E6%A5%B5%E9%99%90
("賴清德二歲時，父親因為煤礦災變意外過世")
There is no need to read the rest.
(iv)
(A) Despite his political belief, Lai was invited to visit Shanghai. Fudan University's president and faculty on June 7, 2014 received him in an affable ambien, where Lai stated:
(d) RFA: "被看好问鼎总统大位的绿营政治明星赖清德，却在台南市议会备询时，脱口说出自己 '亲中、不反中' 谈话。"
(i) He hints that he might run for presidency (as early as 2020, thus challenging president Tsai Ing-wen). The latter is holding tight to DPP chairmanship (hence the party machinery).
(A) The DPP recently released trial balloons to draft 徵召 (bypassing a primary election) Lai to run for 新北市長 in 2018 (thereby encumbering Lai with mayoralty; if Lai does run for presidency, he would be lampooned as another 新北市長 who did the same in 2016: 朱立倫. Kai shot the baloons down.
(B) Then president Tsai tested water by leaking the invitation for Lai to be 總統府秘書長. Lai was not interested.
(ii) AFTERMATH of Lai's June 5 remarks:
(A) 張榮祥, 賴清德：台灣應該要親中 互相合作.中央社, June 6, 2017. http://www.cna.com.tw/news/aipl/201706060118-1.aspx
(B) 被問是否「親中」 蔡英文笑而不回應. 今日新聞 NOWnews, June 7, 2017 https://tw.news.yahoo.com/被問是否-親中-蔡英文笑而不回應-073657694.html
("針對台南市長賴清德日前的「親中愛台」說法，民進黨副祕書長徐佳青今（7）日表示，民進黨與賴清德市長的意見一致；總統蔡英文同日下午面對此問題則笑而不答，快步離開。 * * * 民進黨中常會今日下午邀請科技部政務次長蘇芳慶就「生醫產業創新推動方案」提出專案報告。蔡英文在步入場被問到是否也「親中」時，只對媒體揮手之後，笑而不答的快步進入會場")